WARNING: Prolonged exposure to self-inflicted punching of walls may lead to: Bruises and Scars, Dented Hairline, Lost Sense of Propriety, Fist Bumps and Tennis Elbow, and Uncontrollable Yelling at Inanimate Objects.
Don't say we didn't warn you.
Visit Therapeutic Techniques for When You Can't Stop Punching Walls for more information.
Or, if you're feeling particularly masochistic, visit Self-Punching Sports and Activities to learn how to channel your aggression into something... less destructive.