I have to add, because I worked at a grocery store for three years, lol.

-Yes, the cart thing is annoying as h*ll. Even now, I work at Petco, and granted, we don't have a cart corral, people are still too lazy to walk 20 feet and bring it back in.
-CELL PHONES! Don't get me wrong, my cell phone is my LIFE, but I make an effort to NOT BE RUDE and GET OFF MY PHONE when it's my turn in line, or wait out of line until I'm off the phone. I HATED that as a cashier!
-People getting mad at cashiers for items coming up wrong. Not my fault, thanks!
-Crabby people! If I'm nice to you, please try to be nice to me and acknowledge my existence. Don't take your bad day out on me. =]

I hated working there. People are so rude.

You know what? I think all of us PT'ers should just buy our own town. We'd be wonderfully mannered citizens with tons of lovely animals, lol.