Three startups. Three times I built something people said they wanted. Three times they didn't actually buy it. The pattern was obvious. I was asking "would you use this?" and collecting yeses like they meant something. They didn't. The problem is structural. When you ask someone if they'd use a product, they're predicting their future behavior. Humans are awful at this. We're biased toward yes because we don't want to be negative, and the cost of saying yes is zero, they're not ac...