What makes the irrationality of Silicon Valley so powerful is that people in the thick of it have no concept that they’re being irrational. Every entrepreneur thinks his startup will make it. The biggest risk takers actually don’t see themselves as risk takers. They just clearly see an opening in the market and know they can fill it — whether time proves them right or not. Over and over again you hear this from entrepreneurs: If we’d had any idea what we were taking on, we never would have started this company.