That's a terrible story, unfortunately not all that uncommon. I personally know of one case of a guy honking at the wrong car in front of him, the driver gets out, (just paroled from prison), and punches the guy leaving him out cold w/ his toddler strapped into the baby seat. Permanent brain damage. He is an aquaintence of someone on this board.
These stories go on and on, and still I've been guilty of taking the bait. It is never smart. I feel great when I let someone go ahead of me, sometimes an angry person chills out when you give them a little break/courtesy. One of the best pieces of advice I've ever heard is to "Pause when agitated".....