I knew a couple of guys who were couriers in London. One of their favourite tricks for revenge in heavy traffic was to open the rear door or boot (trunk) of the car that had cut them up. Due to the traffic the car driver would never be able to catch them (certainly not after having to get out and shut the door/boot anyway).
I've had one incident where some lads in a soft top car fired a water pistol at me as I was riding along. The road we were on doubles back on itself and a cycle path cuts through the short part leading to a toucan crossing. I rode through and pressed the button, bringing them to a stop at the red light. I then emptied the contents of one of my bottles all over the occupants and shot off down the cycle path again.
I've had one incident where some lads in a soft top car fired a water pistol at me as I was riding along. The road we were on doubles back on itself and a cycle path cuts through the short part leading to a toucan crossing. I rode through and pressed the button, bringing them to a stop at the red light. I then emptied the contents of one of my bottles all over the occupants and shot off down the cycle path again.