Maybe I am lucky, but have only had one bad experience with Gamestop and have been doing business with them for many years.
Only bad experience was one of their guys trying to convince me to NOT buy a game and telling me another game was better. Thought that was pretty rude actually. I typically do some research before dropping 50-60$ on a game and know what I want.
Other than that, I have a friend who is a manager at our local Gamestop and he is a GREAT guy.
Anyways, good luck with the job!