Given that I was chased down and driven at by a very angry motorist for being so aggressive to lightly shrug at his almost lethally close pass (a 50mph pass within 2 feet), I'm now very careful indeed around car drivers. You never know how unhinged the driver will be, and some of them take apparent criticism VERY personally. My "crime" which prompted him to repeatedly reverse at me had literally been an upturned palm and a tilt of the head, like a mild kind of "Eh? Come on mate what was that?" gesture. Didn't swear, didn't do anything rude, just asked a question.
This guy was quite meek looking too, about early 70s, and yet quite prepared to use his car as a weapon for having his driving ability questioned.
The nice thing is that I know where he lives thanks to him having a wanky private vanity plate that was easy to remember, and I spotted his car some months later at his house, only about 2 miles from me. That one is in the bank for another day.