20 November 2025

Slack founder: Mental models for building products people love ft. Stewart Butterfield

7Frameworks

15Insights

Episode overview

Lenny Rachitsky interviews Flickr and Slack founder Stewart Butterfield about the mental models behind products that create lasting customer value. Butterfield explains utility curves, product taste, comprehension over friction, Parkinson’s Law, hyperrealistic work-like activities, the owner’s delusion, and the origins of “We Don’t Sell Saddles Here.” He also discusses making rational pivot decisions and treating generosity toward customers and employees as both an ethical commitment and a durable strategic advantage.

Key ideas

Features sit on utility curves: early investment may produce little value, a threshold can unlock substantial utility, and further refinement eventually reaches diminishing returns.
Product taste can be developed through practice, empathy, and persistent attention to small conveniences that create emotional attachment and advocacy.
When users lack clear intent or understanding, the central design problem is comprehension—not minimizing clicks, taps, or abstract friction.
Leaders should keep teams focused on known valuable work and prevent organizational growth from producing convincing but low-value work-like activity.
A product team should remain perpetually alert to improvement opportunities while building enough trust that direct criticism becomes useful rather than demoralizing.
Positioning and market creation are part of building the product: communicate the desired outcome and changed way of working, not merely the feature set.
A genuine pivot requires exhausting realistic good options, creating emotional distance, and making a coldly rational expected-value decision.
Long-run business success should be measured by customer value actually created; generous, cooperative policies can reinforce trust with employees and customers.

Transcript available · source text is retained privately and is not published

Frameworks in this episode

Marketing3 steps

Comprehension Over Friction

Removing friction only helps when intent is high; for most of your product the real problem is comprehension

Read →

Communication4 steps

Don't Make Me Think (Reduce Thinking, Not Clicks)

Optimize for the fewest decisions, not the fewest clicks — eight trivial taps beat two fraught ones

Read →

Leadership4 steps

Hyperrealistic Work-Like Activities

As orgs grow, work supply runs out and people fill the gap with fake work that looks exactly like real work

Read →

Entrepreneurship4 steps

The Coldly Rational Pivot Decision

Pivot only after you've exhausted the good ideas — and force emotional distance so the call is rational, not humiliating

Read →

Mindset3 steps

The Owner's Delusion (and the Audience's Illusion)

You overrate your own product because you built it; your users arrive distracted, barely-intending, and ready to bounce

Read →

Innovation4 steps

The Utility Curve

Use the S-curve of effort-to-value to decide whether a feature is under-invested or already maxed out

Read →

Marketing4 steps

We Don't Sell Saddles Here (Sell the Outcome, Create the Market)

Don't sell the product — instill the yearning for what it makes possible, and build the market as you build the product

Read →

People & resources mentioned

Attributed to the moment in the episode. Timestamps are approximate.

People · 12

Stewart ButterfieldMentionsStewart founded Flickr and then Slack, which he sold to Salesforce in one of the biggest acquisitions in tech history at the time.
“Today my guest is Stewart Butterfield, a founder and product legend who rarely does podcasts.”
▶ Watch at ~1:30approx.
Stewart ButterfieldMentionsStewart founded Flickr and then Slack, which he sold to Salesforce in one of the biggest acquisitions in tech history at the time.
“Stewart founded Flickr and then Slack, which he sold to Salesforce in one of the biggest acquisitions in tech history at the time.”
▶ Watch at ~1:30approx.
Cal HendersonMentionsCal Henderson, who's the CTO of Slack, and who also we worked together on Flickr
“Cal Henderson, who's the CTO of Slack, and who also we worked together on Flickr”
▶ Watch at ~5:30approx.
Jeff BezosCoinedthe Jeff Bezos thing that like the success of today was set in motion three years ago
“Bezos used the term divine discontent.”
▶ Watch at ~10:00approx.
Jeff BezosCoinedthe Jeff Bezos thing that like the success of today was set in motion three years ago
“Jeff Bezos line, your margin is my opportunity.”
▶ Watch at ~16:30approx.
Patrick CollisonMentions“there's this tweet by Patrick hollison that I've brought up a couple times on this podcast”
“I'm sorry, Patrick goes up to the Sundar”
▶ Watch at ~40:00approx.
John CollisonMentionsJohn and Patrick were the first marketers at Stripe because they were developers themselves.
“John Collison from Stripe is there”
▶ Watch at ~40:00approx.
Sundar PichaiMentionsGoogle leader whom Benioff praises while discussing Google's AgentSpace.
“Sundar, CEO of Google, is there”
▶ Watch at ~40:00approx.
Ray DalioMentionsRay dalio had this passage in one of his books
“Ray Dalio. Yeah, Ray Dalio.”
▶ Watch at ~48:00approx.
Michael JordanMentionsMichael Jordan used to say that you know I've failed over and over and over and over again
“Michael Jordan learning to ski.”
▶ Watch at ~48:00approx.
Melanie PerkinsMentionsToday, my guest is Melanie Perkins, CEO and co-founder of Canva.
“I just had Melanie Perkins, CEO of Canva on the podcast.”
▶ Watch at ~1:18:00approx.
Lenny RachitskyMentionstoday we've got another very special compilation episode something I've been pulling on more and more with the podcast and the newsletter
“Thank you for having me, Lenny. I really enjoyed it.”
▶ Watch at ~1:30:00approx.

Resources · 25

MIT Technology ReviewMentionswebsite
“I was interviewed by MIT Technology Review and asked if we were working to improve Slack.”
▶ Watch at ~0:00approx.
SlackCoinedsoftware · Slack Technologies
“Stewart founded Flickr and then Slack”
▶ Watch at ~1:30approx.
SalesforceMentionscompany · Salesforce
“Slack, which he sold to Salesforce in one of the biggest acquisitions in tech history at the time.”
▶ Watch at ~1:30approx.
FlickrCoinedwebsite · Stewart Butterfield and team
“Stewart founded Flickr and then Slack”
▶ Watch at ~1:30approx.
Lenny's NewsletterMentionsnewsletter · Lenny Rachitsky
“Head on over to lennysnewsletter.com and click product pass.”
▶ Watch at ~2:30approx.
Lenny's NewsletterMentionsnewsletter · Lenny Rachitsky
“If you become an annual subscriber of my newsletter, you get 17 incredible products for free for an entire year”
▶ Watch at ~2:30approx.
GmailUsessoftware · Google
“Most people have the Gmail calendar app on their phone. I travel a fair bit.”
▶ Watch at ~11:30approx.
TicketmasterMentionscompany
“And you go to the Ticketmaster website.”
▶ Watch at ~29:30approx.
Apple PayUsesproduct · Apple
“I am significantly more likely to buy something if there's Apple Pay or Shop Pay or something like that.”
▶ Watch at ~30:30approx.
Shop PayUsessoftware · Shopify
“I am significantly more likely to buy something if there's Apple Pay or Shop Pay or something like that.”
▶ Watch at ~30:30approx.
Don't Make Me ThinkRecommendsbook · Steve Krug
“And if there is one mantra that I would use to replace that, it's don't make me think.”
▶ Watch at ~36:30approx.
StripeMentionscompany · Patrick Collison and John Collison
“John Collison from Stripe is there”
▶ Watch at ~40:00approx.
GmailMentionssoftware · Google
“The Gmail actions on an individual email are broken into two very long menu items that are different.”
▶ Watch at ~41:00approx.
SnapchatMentionssoftware · Snap Inc.
“I was watching her use Snapchat, and it was insane.”
▶ Watch at ~44:00approx.
Why Nothing WorksRecommendsbook
“There's a book called Why Nothing Works recently”
▶ Watch at ~52:00approx.
Why Nothing WorksMentionsbook
“The content was really incredible. It's just explaining why it's so hard”
▶ Watch at ~52:00approx.
The EconomistMentionswebsite · The Economist Group
“It's an article in The Economist by Parkinson.”
▶ Watch at ~54:30approx.
We Don't Sell Saddles HereCoinedother · Stewart Butterfield
“When people think of Stewart Butterfield, I think a lot of people think of we don't sell saddles here.”
▶ Watch at ~1:08:30approx.
We Don't Sell Saddles HereCoinedother · Stewart Butterfield
“It really was an internal memo”
▶ Watch at ~1:09:00approx.
JawsMentionsfilm · Steven Spielberg
“It's much easier to say it's like Jaws meets Star Wars”
▶ Watch at ~1:11:00approx.
Star WarsMentionsfilm · George Lucas
“It's much easier to say it's like Jaws meets Star Wars”
▶ Watch at ~1:11:00approx.
CanvaMentionscompany · Melanie Perkins, Cliff Obrecht, and Cameron Adams
“I just had Melanie Perkins, CEO of Canva on the podcast.”
▶ Watch at ~1:18:00approx.link ↗
Dharma & GregMentionstv show
“By the time I realized that Dharma and Greg had already come out”
▶ Watch at ~1:26:00approx.
Stuart LittleMentionsfilm
“Any character except for Stuart Little, the mouse”
▶ Watch at ~1:26:00approx.
Lenny's PodcastMentionspodcast · Lenny Rachitsky
“You can find all past episodes or learn more about the show at lennyspodcast.com.”
▶ Watch at ~1:30:00approx.

Spot an error or want something removed? Request a correction or removal.

Insights & moments

The myth-busts, hot takes, explainers, and tools worth keeping.

Hot Take· 7

Hot Take28:30

The Problem Usually Isn't Friction, It's Comprehension

Removing friction only helps when the user already has strong, specific intent — like buying Taylor Swift tickets, where they'll push through a slow site. But most products face low, fuzzy intent, where the real barrier is comprehension: what is this and what do I do next? Butterfield argues 70-80% of product design lives in that comprehension step, and treating everything as a friction problem is a lifelong, misguided battle.

High, specific intent (Taylor Swift tickets) means users persist through friction
Slack visitors arrived just barely over the intent threshold, with fuzzy intent
The real challenge was creating comprehension: what is this, and what do I do next
Most of a product's unique parts are comprehension problems, not friction problems

“is no one needs to be explained why people would want a car or beer. Um but everyone would have to be explained why they…”
Stewart Butterfield · 29:00

“Um It is a a poor approach when the challenge is really comprehension.”
Stewart Butterfield · 33:30

#product#ux#friction#comprehension

Hot Take36:30

"Don't Make Me Think" — The Real Cost of a Decision

Butterfield's replacement mantra for 'reduce friction' is 'don't make me think.' Making a decision has a literal metabolic cost — burning glucose, decision fatigue — but the bigger problem is emotional: software that stops you with a decision you don't understand makes you feel stupid. Users then associate that bad feeling with the product forever.

Deciding is metabolically expensive and causes decision fatigue
The worse cost is emotional: an unclear choice makes users feel dumb
Non-savvy users (e.g. parents) almost always blame themselves, not the software
That negative emotion gets permanently associated with the product

“And if there is one mantra that I would use to replace that, it's don't make me think.”
Stewart Butterfield · 36:30

“One is it's just like it it it's expensive to make a decision. Like you literally burn glucose.”
Stewart Butterfield · 37:00

#ux#product#psychology#simplicity

Hot Take38:30

Reducing Clicks Is Almost Always the Wrong Goal

Chasing fewer clicks is a trap — you could make everything one tap by dumping every option on one endless screen, which is obviously terrible. Better to group options, surface the two or three most common actions, and hide the rest behind 'other.' Butterfield points to old Uber ('Where would you like to go?' plus Other) and a teen tapping Snapchat six times a second: eight easy taps beat two agonizing ones.

You could make any action one tap by exposing everything on a giant scrolling screen — and it'd be awful
Group items, present the 2-3 most common actions, put the rest behind 'other'
Old Uber was just 'Where would you like to go?' plus Other, because that's what people almost always wanted
Eight trivially-easy taps beat two taps where each is a fraught, comparison-heavy decision

“along with reduced friction, it's like reduce the number of clicks or taps it takes for someone to accomplish something, which is almost always exactly…”
Stewart Butterfield · 38:30

“And that was perfect because almost all of the time people just wanted to choose where they wanted to go.”
Stewart Butterfield · 42:30

#ux#product#interaction-design#simplicity

Hot Take46:30

"We Should Be Humiliated We Offer This to the Public"

Asked by MIT Technology Review in 2014 whether Slack was still improving, Butterfield said the product was terrible and they should be humiliated to ship it. Staff printed the quote and pasted it on the wall — but to him it was aspirational: you should feel a perpetual desire to improve. If you can't see almost limitless opportunities to improve, you shouldn't be designing the product.

Said to MIT Technology Review in 2014, the year Slack launched
Employees printed the quote across 40 sheets of paper and posted it on the wall
Being proud of individual pieces is fine; in aggregate, nothing is close to perfect
Ties to Kaizen, Six Sigma, and Ray Dalio's Michael-Jordan-learning-to-ski story about treating every flaw as a gem

“certainly I feel like what we have right now is just a giant piece of [ __ ] Like, it's just terrible, and we should be humiliated…”
Stewart Butterfield · 47:00

“if you can't see almost limitless opportunities to improve, then you shouldn't be designing the product”
Stewart Butterfield · 47:30

#leadership#craft#culture#improvement

Hot Take50:00

Almost Nothing Works: The World Is a Museum of Passion Projects

Politicians sell the idea that things are bad because someone bad is preventing the good — billionaires, immigrants, freeloaders. Butterfield's counter: the reality is that almost nothing works, and getting anything done requires enormous resources plus politicking, sociology, and convincing. He cites the years-long saga of installing a single stop sign and the book 'Why Nothing Works' on the ever-growing number of vetoes blocking any course of action.

The satisfying political story is that goodness is being blocked by a bad actor
The truer story: everything is complex and multivariate, and almost nothing works
A viral thread on the years and agencies required to install one residential stop sign
'The world is a museum of passion projects' — anything that exists survived all the politicking to make it real

“The reality is like almost nothing works.”
Stewart Butterfield · 51:30

“the world is a museum of passion projects”
Stewart Butterfield · 52:00

#organizations#complexity#mental-models#politics

Hot Take1:02:30

Hyperrealistic Work-Like Activities

Startups begin with abundant 'known valuable work to do' — tasks you both understand and know are valuable, like opening a bank account. As headcount outpaces the supply of that work, people fill the gap with hyperrealistic work-like activities: meetings to preview decks for other meetings, superficially identical to real work but fake. Butterfield says it traps everyone, including board members and himself, and the leader's job is to ensure a sufficient supply of known valuable work.

'Known valuable work to do' = tasks you understand and know are valuable
Early startups overflow with it; over time supply of work falls behind headcount
Hyperrealistic work-like activities are superficially identical to real work but produce nothing
It's the leader's responsibility to create clarity and a sufficient supply of known valuable work, not to chide people

“hyperrealistic work-like activities is goes along with this other concept called known valuable work to do.”
Stewart Butterfield · 1:03:00

“And that hyperrealistic work-like activity is superficially identical to work.”
Stewart Butterfield · 1:06:00

#organizations#productivity#leadership#management

Hot Take1:20:30

Generosity as Game Theory (and Good Business)

Asked about his reputation for generosity, Butterfield frames it partly through the prisoner's dilemma: acts of generosity signal that you'll cooperate across repeated interactions, which invites cooperation back. But he insists it's also just true — in the long run you can't destroy value for customers and expect success. He made whole companies chant that the measure of success is the value created for customers.

Generosity signals cooperation in an iterated game, inviting cooperation in return
Ethical operating also attracts a better class of employee and reduces internal problems
In the long run you cannot destroy value for customers and stay successful
There's no substitute for actually having created the value — you can point to it, but you must have made it

“the you know, acts of generosity to me are a way of demonstrating that I am going to cooperate as we iterate in this game.”
Stewart Butterfield · 1:21:00

“it was in the long run, the measure of of our success will be the amount of value that we create for customers.”
Stewart Butterfield · 1:22:00

#leadership#generosity#game-theory#customers

Explainer· 2

Explainer54:00

Parkinson's Law: Why Headcount Only Ever Grows

Parkinson's 1955 maxim — work expands to fill the time available — shows up in his Royal Navy chart where administrators ballooned even as ships and sailors shrank. Butterfield's version: the overwhelming majority of people you hire want to hire more reports, because reports correlate with pay, authority, and career trajectory. It's not evil or stupid; it's an almost overpowering organizational impulse that often leads to disaster.

Work expands to fill the time available for its completion
Parkinson's Navy chart: administrators grew while capital ships and sailors did not
A 27-year-old PM immediately wants a hire so they can 'do strategy'
Reports correlate with pay, authority, and career trajectory — so growth is self-reinforcing

“And uh the maxim is work expands to fill the time available for its completion.”
Stewart Butterfield · 54:30

“the overwhelming majority of people you hire want to hire more people who report to them.”
Stewart Butterfield · 56:30

#organizations#hiring#management#mental-models

Explainer1:26:30

The Owner's Delusion (and the Audience's Illusion)

Butterfield's old example: a restaurant website with slow Ken Burns photos and music but no clickable phone number or hours — even though the owner has been frustrated by exactly that on other sites. He calls it the owner's delusion: you assume your thing matters so much you forget the visitor is a distracted, late-for-work human about to bounce in a fraction of a second. The remedy is to name it, discuss it, and force yourself to look again as a regular person.

Five things you want from a restaurant site: address, phone, menu, hours, reservations
Owners build sites that fail on all five despite being frustrated by that same failure elsewhere
You overrate your own thing and forget the user is distracted and about to bounce
The fix: name and recognize the audience's illusion, then re-examine your product as a regular human

“There's five things you could possibly want when you go to a restaurant's website, and is their street address, their phone number, the menu, the…”
Stewart Butterfield · 1:26:30

“And so everyone should always be conscious of the audience's illusion.”
Stewart Butterfield · 1:29:00

#ux#product#psychology#mental-models

Story· 4

Story17:00

"Tilting Your Umbrella Is Our Opportunity": Craft as Advantage

Walking through rainy Vancouver, Butterfield noticed only about a third of people tilted their umbrellas to let others pass, and turned it into a Slack value. His point: most people don't notice or don't care about their impact on others, so being genuinely considerate and empathic in product design is a rare, defensible advantage. He credits Slack's word-of-mouth growth to exactly these small conveniences that made people form an emotional connection.

Only about 1/3 of people tilted their umbrella to avoid poking oncoming pedestrians
A riff on Bezos's 'your margin is my opportunity' — 'tilting your umbrella is our opportunity'
Failing to be considerate is a competitive advantage others leave on the table
Slack grew via cross-pollination: employees who left for a new startup evangelized it because of that emotional connection

“And so we would say at Slack like tilting your umbrella is our opportunity. You know, that's not a great rephrase of the your margin…”
Stewart Butterfield · 19:00

#craft#taste#product#growth

Story20:30

How Slack Helped Standardize the Magic Link

An engineer questioned why Slack asked for both an email address and a password when owning the email is what let you create the account in the first place. Since typing a strong password on a phone is a terrible experience, Slack's first mobile app just emailed a link that opened the app and authenticated you. Butterfield says they didn't invent the idea but were among the first to scale it into a standard.

Owning the email address is already proof enough to create the account
Typing a hygienic password on a phone is a painful experience
The emailed link auto-opened the app and authenticated the user
Butterfield credits others for the idea but says Slack helped make it a standard

“Why don't we just ask them for their email address and then send them a link?”
Stewart Butterfield · 21:00

“Wow, so you guys invented the magic link uh experience.”
Lenny · 21:30

#authentication#mobile#ux#product

Story23:30

The Shouty Rooster: Shaping Behavior Around @everyone

Like the abused 'important' flag in Outlook, Slack's @everyone triggered an arms race where each person justified notifying the whole channel. Slack's fix was a cartoon rooster ('internally: don't be a cock') that popped up warning exactly how many people across how many time zones would be pinged. It was trivial to build, dramatically cut abuse, and taught users how the product actually worked.

Priority flags and @everyone get abused because one person's use invites everyone else's
The rooster warned, e.g., that a message would notify 147 people in eight time zones
Usage of @everyone dropped off sharply after it shipped
A trivial-to-implement nudge that also taught users the cost of the feature

“So um we came up with what was called the shouty rooster. And internally we said, "Don't be a cock."”
Stewart Butterfield · 24:00

“"Hey, this is going to cause a notification for 147 people in eight different time zones. Are you sure you want to send this message…”
Stewart Butterfield · 24:30

#behavior-design#notifications#craft#product

Story58:30

The Threads @-Mention That Came Back: A Guaranteed Loser

Butterfield killed a feature that pre-populated a thread reply with @previous-poster, both because it taught people to use the product wrong and because he thought it was pointless. Six months later it returned, justified by research showing threads were 2.17 messages long versus 2.14 without it. His point: the possible upside was tiny, but the cost — flags, instrumentation, dashboards, meetings, thousands of person-hours — made it a guaranteed loser.

The reply box pre-filled @previous-poster, which taught users the product's notification model wrong
It returned justified by a 2.17-vs-2.14 average messages-per-thread difference
Why is a longer thread even better? And the difference was statistically marginal
The tiny possible upside was dwarfed by the huge cost to run the analysis

“it was something like when we do this, threads are 2.17 messages long versus 2.14 messages long on average for when we don't do it.”
Stewart Butterfield · 1:00:30

“So, it's guaranteed to be a loser.”
Stewart Butterfield · 1:02:00

#product#metrics#organizations#prioritization

Q&A· 1

Q&A1:13:30

On Pivoting: Be Coldly Rational, Because It's Humiliating

Butterfield, who pivoted both Flickr and Slack out of failed games, says the default advice is always 'persevere' — the kitten hanging on with 'hang in there.' But he argues you have to be coldly rational and honest about whether you've exhausted every non-ridiculous idea. The reason people avoid it is that pivoting is humiliating: you convinced investors, employees, press, and users, and admitting you were wrong is wrenching.

The cultural default is persevere, backed by survivorship-biased success stories
The real test: have you exhausted every non-ridiculous long-shot idea?
People keep going until the company dies of suffocation rather than admit they were wrong
Create distance to make an intellectual, rational decision instead of an emotional one; a few months in isn't a real pivot

“But, you know, the default advice for anyone in anything is persevere.”
Stewart Butterfield · 1:14:30

“And the reason is say you have to be coldly rational about it is because it's [ __ ] humiliating.”
Stewart Butterfield · 1:15:30

#startups#pivoting#decision-making#founders

Takeaway· 1

Takeaway1:08:30

"We Don't Sell Saddles Here": You Create the Market, Not Just the Product

Butterfield's legendary internal memo, written verbatim when Slack was eight people pre-launch, argued it's not enough to build a great product — you must put equal effort into communicating the problem it solves and the outcome it delivers. If your thing differs meaningfully from the alternatives, you're creating the market as much as the product. He leans on the classic reframe: don't sell the saddle, sell the experience of horseback riding.

The memo was verbatim internal comms from when Slack was ~8 people, before launch
Building the product isn't enough — you also have to create the market for it
It's nearly impossible to plant a net-new idea; combine two existing ones ('Uber for pets', 'Jaws meets Star Wars')
Sell the experience, not the object: horseback riding, not the saddle; the open road, not the motorcycle

“from my perspective it's almost impossible to create a net new idea in someone's head. It's much easier to take a couple of existing ideas…”
Stewart Butterfield · 1:11:00

“instead of trying to convince men to build a ship, uh instill a yearning for the sea.”
1:13:00

#positioning#marketing#product#strategy

Key ideas

Frameworks in this episode

Comprehension Over Friction

Don't Make Me Think (Reduce Thinking, Not Clicks)

Hyperrealistic Work-Like Activities

The Coldly Rational Pivot Decision

The Owner's Delusion (and the Audience's Illusion)

The Utility Curve

We Don't Sell Saddles Here (Sell the Outcome, Create the Market)

People & resources mentioned

People · 12

Resources · 25

Insights & moments

◆Hot Take· 7

The Problem Usually Isn't Friction, It's Comprehension

"Don't Make Me Think" — The Real Cost of a Decision

Reducing Clicks Is Almost Always the Wrong Goal

"We Should Be Humiliated We Offer This to the Public"

Almost Nothing Works: The World Is a Museum of Passion Projects

Hyperrealistic Work-Like Activities

Generosity as Game Theory (and Good Business)

✶Explainer· 2

Parkinson's Law: Why Headcount Only Ever Grows

The Owner's Delusion (and the Audience's Illusion)

❝Story· 4

"Tilting Your Umbrella Is Our Opportunity": Craft as Advantage

How Slack Helped Standardize the Magic Link

The Shouty Rooster: Shaping Behavior Around @everyone

The Threads @-Mention That Came Back: A Guaranteed Loser

?Q&A· 1

On Pivoting: Be Coldly Rational, Because It's Humiliating

▲Takeaway· 1

"We Don't Sell Saddles Here": You Create the Market, Not Just the Product

Hot Take· 7

Explainer· 2

Story· 4

Q&A· 1

Takeaway· 1