I used to work at a Hollywood Video. It was the first and last clerk job I've ever held. It was hell. One night, this guy came in and rented Trainspotting. I had seen him a few times before, and when he asked me my opinion, I (foolishly) told him the truth--that I thought it was quite a good movie, etc. etc. About three hours later, he storms back in, waving the video in his hand, screaming about how bad it is, how he can't believe we would carry a movie that glorified drug use in such a way, and so on. It turns out that he ran a church youth group, and had rented it for their post-bible-study movie--smart guy, obviously. He went on and on, asking for the manager (who wasn't there), attacking me personally, and generally pissing me off.
I finally told him to fuck off.
He was absolutely stupified. He stood there with his mouth open for about a minute, then left without another word. He never came back.
That was about the only good thing that happened at that job. I still don't know why I wasn't fired for it. It felt GREAT though. I highly recommend it to anyone who has to suffer through a clerk job.