There's a Louis CK joke where he says something like, "Hey, want to know if you're an asshole? Yeah? Well, if, when you're driving, you ever use your horn to honk at someone, for anything, then you're an asshole."
And for many years, this how I felt. Honking always felt very aggressive and I know it makes me feel bad--indicted--whenever someone honks at me, so I never did it.
But somehow I've changed. Now I honk at someone at least once every other week (perhaps even more often). I try to only honk in the spirit of gentle correction ("Hey, you're about to hit me" or "Hey, the light is green and you should go") but I do sometimes honk at nervous drivers--people who're taking way too long to take a left turn. I am torn about whether this is a good thing to do or not. On the one hand, I know that it doesn't ease their anxiety, and that it probably contributes materially to the stress of turning. But, on the other hand, I also want to let them know that there are standards. I feel like driving is such a personal thing--you're mostly alone in the car and, unless you're driving with your dad, people are reluctant to critique their friends' driving (note--if you critique my driving while we're in the car together, I'm never gonna drive you anywhere again), so I think it might be valuable to people to know that they're being a little too nervous, because otherwise they might never know that it is possible to be better at this.
I like to think that I am Zen, about this. I honk, but never in anger. However, that's mostly an illusion. I'm frequently annoyed when I honk. But I try to be better! And maybe someday I will be.