I work at a grocery store and can attest to all the above It really all comes down to being oblivious to those around you and downright rudeness.
I can add the the list with the kids running thru the store picking up things and dumping them wherever. Stepping on things, opening packages Running up and down the handicap ramp. Mothers completely oblivious.

Additionally, the people that stuff their faces on samples from one end of the store to the other. People with 12 empty sample cups walking around. Better yet, the ones that dump the empty cups anywhere they please..in magazine racks, counter tops, bread bins. It's just disgusting. Empty or half empty coffee cups as well.

A friend of mine once told me "Working retail, you soon realize that Americans SUCK! " LOL. Well, there are the nice ones too. We have customers that make us cakes and stuff. Sorta funny being in a grocery store there's tons to eat but it's the thought