Game Stops are very, VERY dangerous places for fanbois, lol. Probably because the people across the counter is probably a much worse fanboi than you. Or because they're probably trying to meet a sales quota.
Luckily for me, my local gamestop employees know me as that crazy nintendo fanboi who pre-orders a ton, so they keep their mouths shut about my pure nintendo buying habits, and I think they don't even bat an eye anymore when I pre-order games like Dog Island from them. Haha!