All of the VW bug drivers used to wave to each other too.
If you go back to where I was raised in Illinois, all of the old timers still wave when they meet another car. Just a lift your hand up off the wheel thing.
When I am driving the 840, I have people talk to me from the curbs at traffic lights and in parking lots. Cars weave thru traffic to catch up and see what I am driving too.
If I see someone wave I may or may not be able to return the gesture but if you pulled up along side when I have the windows down I would probably participate in a bit of conversation about the car. Old Fartism at its best?or worst?
Now on the other hand when I am driving the Cobra everyone ignores me.