Like ultramar said - if I'm really overly focused on my moods, I'll start tracing things back.

This tends to have a few possible outcomes:
1. I may just find a way to relax myself
2. may learn something new about myself
3. may be introspective and keep tracing things back
4. might end up tracing things back so far that I start to get confused and then go "oh you are being silly, this doesn't make sense!" and usually by that point the emotion will have passed and I'm good to go anyway. Then I just have a laugh at how much over-analyzing I did with no real result!