Its nice to see some of you guys are so friendly, but this whole "waving" thing doesnt work out too well for BMWs. 80% of people who drive BMWs drive them because they need a car and "what the hell, why not a BMW?".
In contrast to people who ride motorcycles who ride motorcycles because "crap, I really want a motorcycle even if my parents are pretty pissed about it". Works out much better when riding a bike.
Edit: And when I'm out on my boat, I only wave to people who have a skier in the water to let them know I see them.