" Violent people have an extremely low tolerance for frustration and lose all emotional and psychological connection with anyone who upsets them. When that connective link breaks, people become objects to be destroyed in the same way as one might smash a tennis racket on the ground following a lousy shot. Remember this if you’re ever dealing with a violent person, because it’ll help you avoid the potentially deadly mistake of appealing to the person’s compassion (“I know you don’t want to hurt me”). Instead, focus all of your efforts on appealing to the person’s self-interest. "

― Mark Goulston , Just Listen: Discover the Secret to Getting Through to Absolutely Anyone