Heh, that happens to me a lot. Every time I see a twin, or a cool BMW in general, I'm driving something else.
Strangely enough, if I let my friend drive my car, he gets waved by every BMW on the road (and other German cars too). I get nothing. But when I drive his car (an STI), I get waves from all the Subaru guys, and he gets nothing. Maybe it's subtle racism ;) (I'm Indian, he's... Dutch? something european lol)