God, fanboy employees. They suck no matter where they're working, and you can find them at movie, comic, and book stores too. You know, sometimes when I go to the store, one of the employees will wander over, ask me if I'm looking for anything in particular, or do the usual, "Have you heard of this game, if you like XYZ you'll really like this" spiel. Which is fine, I'm cool with that. I actually like recommendations because I don't follow the gaming scene all that closely, and it's entirely likely you may have heard of something I haven't.
But every once in a while I run across one who tries to convince me that the game I want is crap; not because it actually IS crap or defective, but because he likes some other franchise or genre better. I don't know if it's because I'm a chick and they assume I'm buying for someone else. I know I don't exactly look like a typical gamer or whatever. (I've actually had employees hand over games going, "I'm sure your husband/boyfriend/whoever you're buying this for is going to love this.") Seriously, if I'm trying to give you money, for the love of God don't try to enforce your personal tastes on me, especially if you're going to be condescending about it. I've never reported anyone to the manager for it (after all, it really isn't worth the trouble, and hey, the person might be having a bad day or whatever) but it's the quickest way to make me walk out and lose a sale.