On my bike....
I just scream into my helmet...
but I have been known to ride along side offending car and look in (with my blue visor) and stare at them, gets them a little off balance.... a gesture is sometimes needed also.
In the car.....
I am known for my complaining.. but thats about it, the occasionaly gesture but only on special occasions... Vauxhall Nova full of 11 year olds for example.
K