PUNCH.HIM.IN.FACE.
even if I got battered i wouldnt regret putting up a fight, as long as I break one of their jaws its all good.
Btw Im not saying violence is a good thing, I'm patient, and would probably empty a milkshake on their head if I had one, but I get a bit crazy when people invade my personal space like that...
What did your friend do?