Read: cop
But seriously, I've never had an major problem with cops. I've been pulled over 4 times. The cops were professional. Didn't get cited any of the four times.
I've encountered police on 3 additional occasions. All three times the cops were absolute dicks. I was breaking no law, and got thrown on the ground on frisked I walked around a corner and bumped into a cop during a big car show in the downtown area of the city. It was quite an accident, I apologized, and he grabbed me and tossed me on the floor. He dug his knee into my back and bruised me up pretty good. It makes me mad that I couldn't hit him back because he was wearing a badge. Anyone else and he would have at least gotten a run for his money. He was a thug, but I'm pretty sure he was just in a pissy mood. No excuse, though.
I guess it depends on which cop, but in general, I don't like them and avoid them as much as possible, on or off duty.