There can be a lot of money in being that guy. I know an entrepreneur who never bothers to check his business plans with even back-of-napkin calculations. He j

There can be a lot of money in being that guy. I know an entrepreneur who never bothers to check his business plans with even back-of-napkin calculations. He just makes Powerpoints. He is an "idea guy", you see. So far he hasn't crashed and burned because he happened to start his first business during the 90s bubble, at the exact same time that other people were making business plans without doing back-of-napkin calculations. And he sold them a lot of stuff. His other terrible business ideas since then haven't yet returned his net worth to where it should be (zero, or negative) because he'd have to live several lifetimes for that. I think this explains a lot about how mind-bogglingly stupid the world can be. Nassim Taleb wrote a whole book on this theme, "Fooled by Randomness".