3. Do something unexpected.
Being impulsive can be a harmless antidote to a dark, brooding mood. Dawn Ferrigno, a nurse from Brooklyn, N.Y., decided to shake off a bad day with a coworker by suddenly taking the Coney Island exit one afternoon and introducing her to the first car of The Cyclone! When you have a chance, break out of your normal routine and explore something new that you otherwise wouldn’t dream of doing. Maybe it’s trying a new dessert at lunch or striking up a conversation with someone at work that you’ve never spoken to before.