There is this really good podcast (imho) "How I Built This", with Guy Raz. If you haven't heard of it, he interviews people who started companies. This past week, he interviewed the founder of Bonobos. He started this company, because his founding partner couldn't find pants that fit. If waist fit, pants were too baggy, and vice versa. I didn't know it was a thing, but many of his friends at business school had the same problem. It reminded me of what your wrote a few entries ago. Spoiler alert, the company was sold to Walmart last year for 350 million. Unfortunately for the founders, their ownership % was watered down a lot by then, so most of the money didn't go to them.