This is very prevelant with the motorcycle crowd as well. I have had a number of sport bikes and I made it a mission to wave at all other motorcycles on the road. I would wave and most motorcycle enthusiasts wave right back. It gives a great sense of community. However more times than not, the leather clad hard core Harley guys would just ride right by and rev their motor with a dirty look. It definitely irritated me but I felt it best to just keep waving.
By the way. I passed a mid 80s Z yesterday with a couple of teenagers. They were completely enjoying themselves with the t-tops off and some music playing. Both waved and I waved right back.
