I keep 2 journals. One is for writing about my feelings (which helps) the other is one that I collect quotes, stories, pictures etc. that struck me as funny, helpful, mindful, or upbeat. When I'm upset I take that out and read through it. That usually helps. I also walk my dogs.

However, I find the best "upper" for me is to clean because usually when I'm in a bad mood or upset I feel out of control of my life/circumstances and cleaning not only helps me feel more in control but also produces visible, tangible results.

I also paint, sew, scrapbook, spend time with children, or sometimes watch a silly movie. Or take a nap. That sometimes helps too.