In all honesty, I try not to worry about what motorists are doing and worry about what I'm doing most of the time. If they shout abuse or honk I'll ignore them. If they get violent I'll go to the cops. If they piss me off, I'll come back and rant about it here. If they are polite I will give them a friendly wave (yes, I've done that sometimes).
My whole point is, that whether they are friend or foe, I have little control over what they are going to do, and so I just try to prepare for it. This doesn't mean that I blame myself for every little conflict (certainly not), but there's little point trying to intimidate someone bigger than you.
And as Feldman said, a little bigotry is very useful. Not so much from a confrontational standpoint, just that it's easier to be prepared for stupid actions from people you don't respect.
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I am clinically insane. I am proud of it.
That is all.