Sometimes it's fun to play with the idiots.
When someone in a truck full of 4 or 5 construction workers shouted, "Nice ass, f**s!" at a bunch of us while on a group ride, I replied "Sorry, I don't swing that way, but it's OK if you do. But I wonder what your buddies are gonna say now that know you think men's asses are nice." About 75-80% of the truck's occupants started laughing their asses off, while the remaining 20-25% looked like they were going to explode.
On a Saturday solo ride, a driver in a work panel truck buzzed me, and when I caught up to him at a red light, he rolled down his window and started the standard, "Get on the sidewalk!" tripe. I replied, "Do you know why you have to work on weekends driving a truck, while I can ride a bike that's worth more than your car? Because you're not only an ignorant idiot that's unaware of the law, you insist in showing off your ignorant idiocy to people you don't even know. If you'd just learn to shut up not as many people would know how stupid you are."
Most of the time I just ignore 'em.