Manners
When we react with anger to someone else, we're generally trying to teach them a lesson. A judge once told me that anger is usually the result of either a loss of control or a perceived loss of dignity; I think that he got it right. When we try to teach another person a lesson, we're trying to show them that they can't take away our control or dignity and get away with it.
Last year I tried a couple of road-rage cases. What is road rage but an effort to teach the other guy a lesson? Driver A makes a mistake, and driver B feels a loss of control. So Driver B then flips driver A off, and driver A feels a loss of dignity. So Driver A brake-checks driver B, and Driver B feels a loss of both control and dignity. So Driver B runs Driver A off the road, and Driver A feels a loss of control and dignity as well. Soon someone is getting shot on the median and someone is getting charged with murder. These things tend to turn brutally expensive for everyone involved really quickly.
The urge to "teach someone else a lesson," or to "show them," or to "teach them manners" is a strong one in our culture. It's so ingrained that some of us aren't embarrassed to write that we think there are situations that "call for being a jerk":
If you cut me off in traffic, then you'll probably get the finger. If you clearly demonstrate that you do not possess any elevator etiquette, then it will be obvious by the look on my face. That kind of stuff.
(Shawn: take this test!)I think the world might be a better place if everyone feeling a loss of control or dignity took a deep breath and considered whether the person responsible could be taught to know better, or whether the likely result would be worth the effort.
It's not my job to teach manners to adults. If you're over 14 years old and don't know to say "please," "thank you," and "I'm sorry," I'm not going to civilize you. I'm not even going to try. If you push onto the elevator before I get off, I'm not even going to scowl. If you cut me off in traffic, you won't be seeing the finger. It'll just waste my time and annoy you. I'm out of the business of teaching grownups lessons.