Everyone's an a**hole till they get runned over by a 200 lb man on a 20 lb bike going at 17+ mph. Physics hurts.
Riding on the Shore Road belt. Theres a joggers lane and a bike lane. A group of older joggers with their Walkman decide to 'jog' on the bike lane. Every few seconds, as bikers pass by, they yell at them to get off the lane. They are oblivious. As I approach, whistle in mouth, I blow like crazy at them, close enough to them so that they can hear the squeel and whistling even above their music. I explain that if a jogger bumps into them, they go ouch. If I bump into them, they're going to the hospital. Pick. They start giving me lip about they can jog where they want to. "Whatever. You want to play with traffic old man, its your funeral not mine."
I hate to say this roadrider, but some people learn through rational discourse, other learn by getting smacked in the head by life a few times. Its that whole "Fire Burns" thing. Some just get it, some need a lighter and some quiet time to figure it out. One of these days the old man is not going to hear the quiet whizzing of a well tuned road bike and the guy on the drop bars may be so into his thing that he doesnt see the old man either. Then, well, Physics does its thing.