Honking in L.A. is sort of a no-go. We're all in the same pot, slowly making the trek home after work, so it's unfair that one of us is rocking the boat and pissing people off even more. But c'mon, don't stop during a green light to decide whether or not you want to make a right turn, and then do it at the last minute so the person behind you misses the green light. Same rule goes for left turns, the moment you have a chance to turn, you better fucking move.
The New York Times gives the traffic problem perspective.