Vulcaneer;
example: A road rage incident. A big man comes at you holding a 2X4. He strikes and damages the mirror on your truck with his board. You get out (empty handed) of the truck to confront him. Do not touch him. Not even a finger on his chest. If he pushes you, you have a right to defend yourself. If he doesn't touch you, you have no right to escalate the conflict.
That's not entirely true. If you can show that a reasonable person would be in fear of their life or of significant harm or that someone else is in danger of death or great harm an individual may use deadly force in almost every state if not all states, (sorry Canadians, I'm unsure of where you'd stand).
If you've climbed out of your truck or car, picked up a 2x4, taken out my mirror and now stand in front of me and aren't apologizing profusely and offering to pay for the damage then it's possible you'd be looking down the barrel of a gun.
Every situation is different and each has it's nuances and twists but, in the end, if you treat every situation like the person in the OP then you are a part of the problem... Bad men and good men and all that...