According to new research, writing down your negative thoughts and throwing them away in a garbage can erase your bad mood. It sounds simple—silly even—but the practice has been found to work. Lead researcher Richard Petty did experiments on 83 people who wrote down thoughts on body image, then threw them away or kept them. People who kept their thoughts were more likely to side with their notes. And if their notes were negative, that's what they held on to. If anything, it can't hurt to try.