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  1. Lenny's Podcast: Product | Career | Growth
  2. Slack founder: Mental models for building products people love ft. Stewart Butterfield
Slack founder: Mental models for building products people love ft. Stewart Butterfield

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

Lenny's Podcast: Product | Career | Growth · Nov 20, 2025

Slack founder Stewart Butterfield on utility curves, craft, and why comprehension beats reducing friction. A masterclass in product building.

Create Advantage Through "Tilting the Umbrella" Empathy

A failure to show basic courtesy, like tilting an umbrella for someone on a sidewalk, is analogous to inconsiderate product design. Most products are oblivious to their user's experience. Building with genuine empathy and consideration is a powerful, rare competitive advantage that fosters emotional connection and advocacy.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago

Parkinson's Law Creates Self-Justifying Organizational Bloat

Work expands to fill time, and organizations expand to fill available work. People instinctively want to hire direct reports to increase their status, creating a supply of labor that then invents low-value tasks to justify its existence, leading to bloat and inefficiency.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago

Use Utility Curves to Guide Feature Investment

Features follow an S-curve of value. Early effort yields little, then a steep rise, then diminishing returns. Use this model to determine if a feature needs more investment to become valuable or if you've already extracted its maximum worth and should stop investing.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago

Pivoting is an Act of Cold Rationality

Deciding to pivot isn't about perseverance; it's a cold, rational decision made when you've exhausted all non-ridiculous ideas for success. The main barrier is emotional—it's "fucking humiliating" to admit you were wrong. The key is to separate the intellectual decision from the emotional cost.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago

The Goal is Zero Thinking, Not Fewer Clicks

Reducing the number of clicks is a misguided metric. A process with eight trivially easy clicks is better than one with two fraught, confusing decisions. Each decision burns cognitive energy and risks making the user feel stupid. The ultimate design goal should be to prevent users from having to think.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago

Cultivate Perpetual Dissatisfaction With Your Own Product

The belief that your current product is "a giant piece of shit" is a powerful motivator. This mindset ensures you are constantly seeking limitless opportunities for improvement. If you can't see flaws and feel a degree of humiliation about what you offer the public, you shouldn't be designing the product.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago

Generosity Is a Winning Strategy in Game Theory

Generosity towards employees and customers is more than just good ethics; it's a strategic move in the iterated game of business. It signals your intent to cooperate, which encourages reciprocal cooperation from others. This builds trust and leads to superior long-term outcomes versus a defect-first approach.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago

Stop Reducing Friction; Start Increasing Comprehension

The obsession with removing friction is often wrong. When users have low intent or understanding, the goal isn't to speed them up but to build their comprehension of your product's value. If software asks you to make a decision you don't understand, it makes you feel stupid, which is the ultimate failure.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago

Beware "Hyper-Realistic Work-Like Activities"

As companies scale, the supply of obvious, valuable work dwindles. To stay busy, employees engage in "hyper-realistic work-like activities"—tasks that mimic real work (e.g., meetings to review decks for other meetings) but generate no value. It's a leader's job to create a sufficient supply of *known valuable work*.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago

Fight the "Owner's Delusion" to See Your Product Clearly

The "Owner's Delusion" is the inability to see your own product from the perspective of a new user who lacks context. You forget they are busy, distracted, and have minimal intent. This leads to confusing UIs. The antidote is to consciously step back, "pretend you're a regular human being," and see if it still makes sense.

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

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

Lenny's Podcast: Product | Career | Growth·3 months ago