So far no one has ever yelled at me while I was on my bike, but it's happened to me in the car (for doing things like, say, daring to stop at a yellow when I clearly have plenty of time to do so). Sometimes I will just ignore them, or succumb to yelling back or fliipping them off (I know, not a good idea, but I'm not perfect)...but sometimes I will just grin maniacally and wave frantically. They probably think I am mentally challenged in some way. But I love the idea of confusing them and making them think that I have no idea that I was just insulted, or that I made them mad.

If I know I've truly done something wrong, I'll just give an apologetic wave. It's when I feel that the other person is just being a jerk that I'll do the other things.