I'm just re-reading this thread and it makes me think,
Other people's behaviour is not my responsibility, but my reaction to their behaviour is my responsibility. That's something I try to keep in mind always when I'm on the road! (I am no saint though - occasionally I'll shout, but I never get physical. I shouldn't even shout though ... I'm working on it!

).
Consider the following situation: Car full of chavs deliberately close-passes, shout abuse as they do so. I can't do anything about that.
What I want to do is catch them up, smash the car up and punch the crap out of them if they get out of the car.
What I actually do is mutter "twats!" under my breath and just carry on riding. This isn't because I'm incapable of defending myself; quite the opposite! I just would rather not end up in prison for pummeling someone into a bloody heap. Nor would I like to spend a week layed up on the sofa having been pummelled into a bloody heap!
It's said that where road rage is concerned, the number one golden rule is absolutely do not react, no eye contact, nothing.
I'm thinking about the two possible outcomes.
1) If I react the way I want to; there can't be a good outcome. If they end up beating the crap out of me, then it will take me a while to recover. If I end up beating the crap out of them, then I will spend the next few weeks absolutely terrified of being convicted of GBH, sent to prison, loose my livelyhood, etc ...
2) When I react the way that I actually do (i.e. no reaction, or as little as I can help), then the whole incident is over and done with in a fraction of a second. The thing is, the people who drive like @rseholes round cyclists sometimes
want a reaction. If you don't give them one, they get bored and leave you alone. Same rule applies when I'm in the car and being aggressively tailgated by someone - I don't react and ... they drop back and stop beeping/flashing/tailgating ... because they get bored because I won't react. It's "playground mentality". Gotta rise above it.
EDIT: I've only ever in my whole life been in one road rage situation where not reacting had no effect and the guy just kept on getting angrier with no provocation whatsoever. I think this guy was probably on drugs/a psychopath - hence totally out of the ordinary.