Ahh the self-gratification artist. Would it have seemed childish to shout I know you are, but what am I?
A BMW driver once gave me the self-gratification artist sign when passing me, then wound down his window at the lights when I caught up. He asked what the hell I thought I was doing on the road? I replied "I'm moving through traffic quicker than I would in my car, and I'm getting some exercise to avoid becoming fat like you." Then I left him and filtered away on a cushion of smugness.
He was very fat.
Don't let it get you down. The nice comments far outweigh the negatives on a 'bent. Unless you're riding a 2 wheel high racer.....I used to get a bit of verbal hassle on that.