I like to give as good as I get. A couple of years ago riding through a busy area on the way to work, some spotty chav informed me that I should work harder to be able to afford a car. The lights were red, so I had plenty of time to "chat" with it. I informed it that if he were to try and sell his ancient Mk 1 Chavalier, he'd be very lucky to get 200 quid for it. And if I were to sell the bicycle I was on I'd be disappointed to get less than 2 grand. The lights went green, he didn't move because the traffic was so heavy - I just rode round all the cars flicking him the bird.
Another time on tour:
Bloke in cage: "Why don't you get off the FUCKING ROAD!!?"
Us: Bikes down, chests out "COME ON THEN YOU FUCKING CAAAAAAAAAHNT"
Bloke in cage: Head down, into first, sheepishly drives off...