Had this happen a time or two in my life. I have a full cart and stand at the back of a line with others with full carts. No one is in the 10 items only line, the cashier signals me to come to her/his empty line.
Soon as I begin to unload customers jump out of the isles [bushes] with 6-7 items. Lots of muttering behind me, "Can't she read , the nerve of that woman" Now if I can hear them I am sure the cashier can too. Does the cashier smile and try to make piece for me as eye balls dart death threats at me ? Hell No, I just have to walk out and hope to heavens I do not run into any of these people in another store.
Old folks, those that dither over finding change in their pockets or purse, no problem, if they need a dime or quarter, I have the change at hand-----I will donate it to keep the line moving on. The elderly may only get out of the house once a week to shop and dress as though they were going to Church. This generation is the proud and would not think of going into public unless all spiffed up.
Unruly kids, ah now one must have patience as little ones get tired and cranky, some are manipulators from Hell. Darn if they act like this at home, say a prayer for the parents. I find it easier to just back up and hit that isle after they move on.
Shopping is a very human activity and should have to have some rules of deportment and conduct. Unfortunately to days shopping has become a rules of engagement. Shopping has gone from a social scene, meeting long lost friends to full ahead let's get my aggression out on someone that cannot or will not fight back.
Seems I have seen more aggressive people bullying folk in a grocery store then in a biker bar.