Road Rage

Why is it that some people are so disrespectful and cut you off while driving. It drives me nuts. I honk my horn so that they know they made me mad. I know there are some gestures that I could do at them but I don't want to be disrespectful like they were when they cut you while driving. I do sometimes though throw my hand up in the air but that's fit. I don't flip the bird as some people call it.