10) They're way too cool to acknowledge any non-Harley riders.
9) They're too busy daydreaming about owning a real motorcycle.
8) Their engine is too weak to handle the added wind resistance of a waving hand.
7) The Rottie (in back of the pickup truck with the tied down Harley) is easily upset by rapid hand movements.
6) Are you kidding? Risk their lives trying to control a Harley with just one hand!
5) They're too busy humming "Born to be Wild" while fantasizing about being Peter Fonda or Dennis Hopper.
4) They're too busy figuring out how to pay for the next order of genuine Harley accessories (including the "official" HD calculator needed to add up the cost).
3) If we really have to tell you, you won't understand anyway.
2) They can't see you because their half-shell helmet keeps falling down over their eyes.
1) They think we are actually trying to draw their attention to the parts falling off their bikes, and they are sick and tired of it.