I used to not care about them, like all. I mean sure I heard the employee horror stories but their really high prices were more then enough to keep me away, although I did get some amusement seeing how their tiny discount for a used game was easily more expensive then brand new copies out there.
What did set to the "hate" category(although it's more of a grudge) is this little story from earlier this year
Tiamattt said:
Last x-mas a friend got me 2 games from them along with gift receipts just in case I didn't like them and wanted to trade them in for something else. While I appreciated the gifts I was in the market for a 3ds and wanted to trade the games in for a discount. The receipts had a date I can trade them in for as long as they weren't open, which was like a month after x-mas. But when I tried I got some BS about how "oh you can only do that a week after it was purchased" despite nothing of the sort being written on the receipt. So I asked what could they do for me and they said I had to go home, open them and then come back another day so they can pay me used game prices for them, which btw was nothing compared to selling them on ebay.
The moral of the story is do NOT get gift receipts for your friends at gamestop, they're literally worthless pieces of paper.
So that set me from ignoring to hating plus happy to encourage friends/family to shop elsewhere.