Here is a great idea that came up driving home from lunch. Cars should have two horns. The first horn would be the nice horn. It's the one you honk for thanking someone or just getting their attention. It would probably sound like a clown car horn, cute and high pitched. The second horn would be the one you use to tell people off. It would sound gruff and rude, like a large man yelling profanity, because that is what it's for.
I think this would add a real depth to travel on the nations roadways. As it is I just use my horn to tell people off, but with two I have so much more depth. I can practically converse with them.