slapped by a cop

These two guys are riding in a car along the highway. The driver is speeding and a state trooper pulls him over. The cop approaches the car and asks the driver for his license and registration. The driver asks what he did wrong. The cop says nothing, hands the driver back his information, rears back, and smacks the shit out of him. The cop gets in his car and leaves. The driver, being confused as to why he was slapped does the only thing he can do, he rolls up his window and drives off. A few minutes goes by and the same state trooper pulls up behind the driver and pulls him over, AGAIN! This time, the cop approaches the passenger side. The passenger rolls down his window and before he can get a word out the cop smacks the shit out of him as well. The passenger yells "what did you do that for?!" The cops leans forward, smiles, and says "cause back there I know you looked at your buddy and said 'I wish the mother fucker would have smacked me like that!' "