I used to yell, give the finger, bang on hoods, etc. but gave all that stuff up years ago. Now, I just expect that a very small minority of drivers won't be perfect- some inadvertently, some maliciously. So what, I'm not perfect either. I just drive predictably and defensively. If some jerk yells or honks just because they don't like bicyclists on the road, I try to make a very friendly wave to mess with them - or maybe if I'm stationary, hold my hand cupped to my ear as if I want them to yell louder because I can't hear them.