Man, a potato from a moving car is gonna be a pain that will linger.
I've had a cigarette thrown and a bunch of off-the-road-****** yells here in the redneck south, but nothing too dangerous. So far.
A few times when I've gotten the yells I've blown a kiss to the yeller, but then I realized there are too many crazy people in the world, and there's no way a bike will win a fight with a car, so I've stopped responding. I think the best advice is to ignore what you can and get the plates if you can.
The good thing is, for every three off-the-road-****** calls, I get one hey-nice-legs call from a car full of girls. Not so bad...