Founders confuse complaining with market demand all the time.
You're hanging out with a group of friends. Someone complains about something and everyone in the group agrees ("oh, man, that's THE WORST"). You walk out convinced you've found product-market fit and start building.
This isn't a hypothetical. This happened to me multiple times in my startup career.
You haven't found anything except a comfortable echo chamber. You've validated frustration. You have not validated anyone's willingness to do anything about it.
This trap exists because complaints are demand-shaped. They look, sound and smell like demand and they activate the same dopamine that closing a deal activates. Sadly, it's way easier to get people to complain than purchase.
Most complaints are social behavior, not market signal. People bitch to bond. They bitch to illustrate expertise. They bitch because their friend bitched and they're showing tribal solidarity. The complaint serves its entire purpose in the moment of complaining. A solution doesn't matter.
This is why crowdsourced lists of "things that should exist" are graveyards. Every popular tweet that asks "WHY isn't there an app that does X" gets 12,000 likes and produces zero paying customers when someone actually builds it. The likes were the product.
The test isn't whether someone complains. The test is what they've already done to solve the problem. If they haven't already tried a handful of solutions and found them lacking, they aren't going to try yours either.
I see this pattern in coaching every quarter. A founder gets a pile of waitlist signups, feels brilliant, launches, converts fewer than 10 to paid and suddenly feels very not brilliant. The 190 who didn't pay are all still interested... they're waiting for another feature, a Chrome extension, a friend to recommend it, the right phase of the moon.
They were never going to buy. They just the idea of a solution in the same way my mom occasionally buys Powerball tickets and spends a week fantasizing about how she'll spend her winnings. She knows she isn't going to win, but the mental vacation makes her happy.
The solution is to sell the thing before you build it. I know that sounds insane. People need to see the product, right? They need to use the demo, right?
I have a client right now who has spent the last several years unsuccessfully selling a product the market ultimately had no interest in. Last month, he started selling a new product that hasn't been built yet and, no lie, customers are now buying failed Product #1 in order to get in on a summer beta of Product #2.
That's market pull :)