The heat of the moment is a powerful, dangerous thing. We all know this. If we’re happy, we may be overly generous. Maybe we leave a big tip, or buy a boat. If we’re irritated, we may snap. Maybe we rifle off that nasty e-mail to the boss, or punch someone. And for that fleeting second, we feel great. But the regret—and the consequences of that decision—may last years, a whole career, or even a lifetime. At least the regret will serve us well, right? Lesson learned—maybe. Maybe not. My friend Eduardo Andrade and I wondered if emotions could influence how people make decisions even after the heat or anxiety or exhilaration wears off. We suspected they could. As research going back to Festinger’s cognitive dissonance theory suggests, the problem with emotional decisions is that our actions loom larger than the conditions under which the decisions were made. When we confront a situation, our mind looks for a precedent among past actions without regard to whether a decision was made in emotional or unemotional circumstances. Which means we end up repeating our mistakes, even after we’ve cooled off.