I heard a good quote from George Carlin after his death a few weeks ago. It went something like:
remember the average person's IQ is pretty low...and half the people are stupider than that.


Generally speaking I let most angry motorists go. Yelling back and inflaming an unknown quantity can be dangerous. I learned my lesson in the car a couple of years ago when a guy cut me off horribly, and I gave him the finger. He then slammed on his brakes and in rush hour traffic walked back to my car and opened my door which I wasn't expecting (thought we were going to exchange words). He then opened his pants (I can't make this crp up) pulled it out and asked me over and over if I was trying to f him. Since I couldn't reach for the door to pull it shut I told him if he didn't back off I was going to kick him and he'd end up in traffic. I grabbed my phone called 911, and he headed back to his car where he proceeded to drive at 5mph for 100 yards up an on ramp and then 25mph on the highway trying to get me to pass him.

I learned an important lesson that day. Venting my own anger at others because of their actions doesn't make a situation better or change the other person's mind, but it can escalate it. The reality is that I let 90% of those situations go, but if someone does something that really endangers me I'll try and calmly let them know, but I won't get into an argument about it.

I also ride with a handlebar camera, and knowing that if I maintain calm behavior while recording the other person's illogical ranting it makes for a better case with the police should I want to make an issue of it.