I've only had two unpleasant experiences with police, one was a state trooper.
(both of these were traffic related, I'm not a criminal of any sort.)
I was driving down a country 2-lane road, and there was a slow ass car and a slow ass truck in front of me. I said F this, and passed them. Of all the dumb luck, the truck driver apparently knew the local sheriff and ratted me out. I was only going 12 miles above the speed limit, and it was a dotted line, so I figured I was in the right to speed up to pass them. What I didn't know was that you can't pass more then one person at a time on a two-lane road. Seriously never know that before. So I'm putting along, and 15 minutes later I come across two more slow ass vehicles, and do the same thing. Unfortunately, a cop was coming in the opposite direction and saw me, and pulled me over. So I say what the heck man, (not in those words) I was just passing. So then I learned about the one car at a time pass rule, PLUS those assholes behind me told this guy I did it before he saw me, so now I've done it twice. I get a $300 ticket, and I have to come back to bumfuck to appear in traffic court. -but that isn't the part that blew me away.
So I show up in traffic court at bumfuck county, the judge calls my name, and the state trooper tells the judge, I shit you not. "He was going so fast when he passed, that I had to swerve to avoid him." I looked at this guy like WHAT THE FUUUUUCK?!" It came the fuck out of nowhere. I couldn't believe this guy was lying in court over something so petty. I was MILES away from this cop when he saw me passing down the road. I was honestly pissed off that this fuckhead was lying and didn't even care about the ticket any more. I looked at him like "why are you lying about this stupid petty charge? I'm getting the ticket regardless, what is the point of adding that story? You're supposed to stand for truth and justice!" Unfortunately, I wasn't quick witted at the time. I was younger and didn't have the balls to speak up or dispute the case, so I just sank and pleaded guilty, paid the $300 and left. Looking back, I should have asked them to pull his dash cam so they could see how ludicrous his accusation was. I should have said "if he had been in any danger of me hitting him, I would have been hauled to jail that day, or at least gotten a wreckless driving charge." Pissed me off for a long time, though it didn't ruin my opinion of police, just that fucker.