I was once in a horrible mood... I felt really guilty/regretful about something I'd done earlier, and felt terrible. Then I was distracted for about half an hour by math homework, and when I was walking outside a few minutes later I caught myself whistling. I was like "Whoa, self! You're supposed to be upset right now!" and almost descended back into the pit of despair, but then I stopped midstride and said "Wait a sec. Why would I want to be upset?" and so I didn't. I kept whistling and had a great day.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.