There's just no nice way to say it: You're stupid with your money. You may fancy yourself a shrewd investor, but if you have normal human instincts—if you stand up and cheer at sporting events, if you follow the crowd toward the exit at the theater—then you have the instincts that make investors alternate between delirious greed and inconsolable fear. Like most of your peers, you are wired to buy high and sell low, and that's why Richard Peterson is about to become one very rich psychiatrist.