This mentality that somehow you have the right to control the way someone else looks at you is right from the egomaniac pits of hell. I don't care if they give you a death-stare behind two fully-extended middle fingers and say fuck your mother, YOU don't have the right to do ANYTHING to them. The only appropriate physical responses are in situations where they are putting you, or someone else, at risk of bodily harm or trying to steal / damage property.