I've found that it's a good idea to avoid the county roads anywhere near the local high school, around the time school lets out. Those hormonal bastages are like prisoners after a jailbreak, and are quick to yell insults, and even toss plastic drink bottles, and they have no concern with giving the cyclist some elbow room. It's best just to not be in the vicitinty around 3:00 p.m.
As mentioned above, the best course of action is to ignore it, or be as nice as possible. Many of us are too old to be street fighting, and we sure don't have the right shoes on for it, LOL!!
Though this will probably offend some snowflakes, on occasion I'll tote my Ga carry permit and a little Airweight 38 pistol. No problem is a jersey pocket. I often ride in secluded, rural areas where witnesses are few and far between, so if a couple uptight hillbillies wanna stop the truck and start something, I'm at a huge disadvantage, and some sort of substantive deterrent could be invaluable (and BTW, I look at a carry piece primarilly as a deterrent, to avoid full-blown violence, rather than a way to facilitate it.)