I'm really shocked so many people find this rude. I mean it's the same thing as a text, it just means "I'm here". I could see how people might find it rude because you are avoiding saying hi to their families (depending on what your relationship is), but a text does the same thing and no one seems to find that rude. Now I get how laying on the horn or beeping at odd hours would be rude, but I don't understand why a simple honk-honk during normal waking hours would be rude. Maybe people just have a negative association with car horns.