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20 November 2025

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

7Frameworks
15Insights

Frameworks in this episode

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