No matter how nice I am it doesn't seem to matter since the employees 90% of the time will act like I'm imposing. So I can say please and thank you and be as cordial as can be and they'll still be rude asshats who don't wanna do their fuckin' job.
I sometimes get the same rude attitude, but I don't care as long as I get them to scan the games. The end result is more inmportant than attitude.
Long time ago, I got a rude employee who said "all the sticker prices are correct" (and didn't want to scan the games with his handheld)...so I told him "ok I want that, and that, and that" (even games I knew were full price). I picked over 25 games, had him carry them to the register, and told him "read each price from the computer" then picked a few clearance games and told him "I don't want the others......lets go pick up some more games". He had a WTF attitude, I told him "hey, I tried to make you life easier, but now you learned that hard way". I picked another 20+ games and ended up buying maybe 6 games total.