Several years ago when I was living in Boston, I called a driver an a**hole after he ran a red light on Storrow Drive and almost ran me over. He actually made a complete U-turn in a busy intersection and started to chase me. When I rode the wrong way on a one-way street to try to lose him, he circled around and cut me off. He was about to beat the crap out of me when another driver pulled up. The second driver, who was over six feet tall and pretty beefy, said he was an off-duty cop, and was going to run us both in unless we stopped fighting. The angry driver took off, and then the second driver told me he wasn't really a cop but had judt gotten mugged in Central Park in NYC the week before and wished that someone had intervened when he was attacked. Now I just ignore angry drivers unless they do something life-threatening, in which case I would yell "help" at the top of my lungs.