I've always believed deeply in this idea. The value of delusion, or rather, calculated delusion, is extremely important to the idea of being entrepreneurial. (Genius here is a bit loosely used, but I'll go with it). The math of any unlikely opportunity (like starting a business) is against you so any logical person would think it's delusional. But to most entrepreneurs, starting a business is all that seems logical. The fastest way to make a billion dollars is take something that everyone believes is true, and bet against it.
http://ashoknayar.wordpress.com/2010/05/27/why-entrepreneurs...