Why do smart people fall for stupid things? Here is what I think is an important part of the answer that almost never gets discussed. It's easy to look around at the stupid seeming things that other people believe (e.g., people who join harmful cults, get scammed by a con artist, become vocal evangelists for a placebo treatment, or jump on the hype train of some outrageous new bubble) and wonder: "How on earth can they be so dumb?" The answer, a lot of times, is simply the trust they have...