What's really weird is that sometimes when you don't do this, logically choosing the appropriate emotion, you're actually sort of doing the opposite, illogically choosing an inappropriate emotion.

For example, let's say that you're angry at somebody for something they did. If you pay attention, you'll notice that you actually don't stay angry the whole time. What happens is that you start to feel less angry, like you are just about over it, and then you think about that thing they did, and you get angry again. It's not completely conscious, but you're choosing to remain angry, usually for no reason. If you just didn't think about that thing, you'd stop being angry.

For me, I've noticed that when I do this sort of illogical thing, I can't seem to get past it until I go to sleep that night. Sleep seems to break the pattern. But most of the time, I can control it nowadays.