I do when it necessitates.
Like an hour ago I was in the lane to turn right with 2 cars ahead of me at a red light. We then got a green arrow to go. The first car sat, and sat, and sat. I honked one nice honk. Nothing. Then another. Nothing. Then I honked like 5 small "beep beep beep" honks and he finally went.
THEN this guy next to me has the nerve to say "Hey whats with the honking".
First off you aren't in this lane so mind your own business and second, what part of green arrow do YOU not understand? I'd venture to guess had HE had someone sit at a green arrow in front of him he wouldn't have been so passive.
Then when I finally turned and passed the butthead in the gigantic Mercedes that was sitting there at the green arrow, he was on his cellphone.
I hate people.
So if you use your horn, do you use it wisely? Do you get angry when someone uses their horn?