The founder of Slack and Flickr on the "owner's delusion," why reducing friction can be counterproductive, why generous leadership wins and more

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

Lenny Rachitsky – Nov 20, 2025

Stewart Butterfield is the co‑founder of Slack and Flickr, two of the most influential products in internet history. After selling Slack to Salesforce in one of tech’s biggest acquisitions, he’s been focused on family, philanthropy, and creative projects. In this rare podcast appearance, Stewart shares the product frameworks and leadership principles that most contributed to his success. From “utility curves” to “the owner’s delusion” to “hyper‑realistic work‑like activities,” his thoughts on craft, strategy, and leadership apply to anyone building products or leading teams.

We discuss

1. Hyper‑realistic work‑like activities – 01:03:17

2. The owner’s delusion – 01:26:34

3. Utility curves – 06:44

4. “Don’t make me think” – 36:55

5. “We don’t sell saddles here” – 01:08:30

6. Tilting your umbrella – 19:03

7. When to pivot – 01:13:23

YouTube →

Also available on Spotify and Apple Podcasts.

Where to find Stewart Butterfield

• X: https://x.com/stewart

• LinkedIn: https://www.linkedin.com/in/butterfield

Referenced

• Slack: https://slack.com

• Flickr: https://www.flickr.com

• Cal Henderson on LinkedIn: https://www.linkedin.com/in/iamcal

• Blok: https://blok.so

• Brandon Velestuk on LinkedIn: https://www.linkedin.com/in/brandon-velestuk-6018721b

• Magic Link: https://en.wikipedia.org/wiki/Magic_Link

• Ticketmaster: https://www.ticketmaster.com

• John Collison on X: https://x.com/collision

• Patrick Collison on X: https://x.com/patrickc

• Sundar Pichai on LinkedIn: https://www.linkedin.com/in/sundarpichai

• “Three Questions with Slack’s CEO”: https://www.technologyreview.com/2014/11/21/170330/three-questions-with-slacks-ceo

• Six Sigma: https://www.6sigma.us

• “What is kaizen and how does Toyota use it?”: https://mag.toyota.co.uk/kaizen-toyota-production-system

• John Collison’s post on X about passion projects: https://x.com/collision/status/1529452415346302976

• Parkinson’s law: https://www.economist.com/news/1955/11/19/parkinsons-law

• “We Don’t Sell Saddles Here” (Medium): https://medium.com/@stewart/we-dont-sell-saddles-here-4c59524d650d

• Glitch (video game): https://en.wikipedia.org/wiki/Glitch_(video_game)

• IRC: https://en.wikipedia.org/wiki/IRC

• Annie Duke on better decision‑making: https://www.lennysnewsletter.com/p/making-better-decisions-annie-duke

• Melanie Perkins on building Canva: https://www.lennysnewsletter.com/p/the-making-of-canva

• Prisoner’s dilemma: https://en.wikipedia.org/wiki/Prisoner%27s_dilemma

• Stewart Little: https://en.wikipedia.org/wiki/Stuart_Little

• Dharma & Greg: https://en.wikipedia.org/wiki/Dharma_%26_Greg

• Stewart’s X post referencing “the owner’s delusion”: https://x.com/stewart/status/1223286626991796224

Recommended books

• Principles: Life and Work – https://www.amazon.com/Principles-Life-Work-Ray-Dalio/dp/1501124021

• Why Nothing Works: Who Killed Progress―and How to Bring It Back – https://www.amazon.com/Why-Nothing-Works-Killed-Progress_and/dp/154170021X

• Positioning: The Battle for Your Mind – https://www.amazon.com/Positioning-Battle-Your-Al-Ries/dp/0071373586

• Quit: The Power of Knowing When to Walk Away – https://www.amazon.com/Quit-Power-Knowing-When-Walk/dp/0593422996

Production and marketing by https://penname.co/. For sponsorship inquiries, email the address provided in the original article.

My biggest takeaways from this conversation

(Content to be added by the author.)