You sure it wasn't your head?????
In all seriousness it grinds my gears when people knowingly drive off after damaging your car.
Saw someone do it in Tesco car park a few months back, side swiped the car parked next to him quite hard as he reversed out of the space. I waited around for a bit and gave the owner the details, I hope the police got involved and he got done with leaving the scene of an accident to be honest.