Learn to let go of grudges and avoid moping.
It can be cathartic to blow off some steam after an intense confrontation, but you can't let that unchecked anger turn into resentment or, even worse, uncontrollable rage.
For example, when Sheldon's jealousy of Bert's MacArthur Genius Grant got the better of him, the theoretical physicist took out his frustration on a boulder. And then a water fountain. In the end, though, Sheldon came to terms with the ordeal and put the past behind him.
After all, bruises tend to heal with time, regardless of whether or not you inflict the injuries upon yourself.