True that! I once got honked at while out for a run, and was tempted to flip off the person who did it because getting honked at like that bugs me. But I resisted the urge and just ignored it. Then later I found out it was my roommate's dad who honked, but I didn't see who was in the car. Imagine how embarrassed I would have been if I had flown the bird instead of just ignoring it! I don't do the smile and wave thing for stuff like that or for comments/catcalls from guys because I don't want them to interpret it as flirting with them. For someone just being plain rude, it would probably work quite well (I haven't run into much of that so far).