“If you feel crappy, it's because that's your brain telling you that there's a problem unaddressed or an issue unresolved. In other words, negative emotions are a call to action. When you feel them, it's because you're supposed to do something. Positive emotions, on the other hand, are rewards for taking proper action. When you feel them, life seems simple and there is nothing else to do but enjoy it. Then like everything else, positive emotions go away, because more problems inevitably emerge.”