I have (and do) wave to pretty much all wheelers, however, I almost never get waves back from anybody except toys. I do NOT, however, wave to fullsize guys. They all have this look that just screams "eat 
, little guy!" Or at least around here...
X2 on that, i like to get in their way, they might be big but they dont have the balls to do anything that might scratch their PC truck.
PC= thingy compensator
