Respect elderly people, don't crush them into the tins of canned tomatoes (limit 4).
People with babies and children always have right of way. Shopping with small children is stressful. Don't believe me? I regularly go shopping with Batman, Spiderman and Princess KungFu, you're are welcome to join us experience this.
If you take a twin trolley and you don't have twins, you just really like having that extra seat to put your handbag in, please, please please don't do it when I am at the supermarket because, as a mother of twins, I will not be able to stop myself from saying something sarcastic on you about how your second baby is looking a bit leathery or similar.
Keep left with your trolley and don't park it erratically in the middle of the aisle. This is not rocket science.
'12 items or less' the sign says, not, 'That's for everyone else, not you, you're special, you can have 14 items'.
You're writing to pay and the person behind you is about to start unloading their groceries. Don't make them lean across to get the divider, put it there for them or pass it to them.
Do not squeeze the fruit. Do not sneeze on the fruit. Do not cough on the fruit. Do not bite the fruit and put it back.
Don't treat the person at the checkout as if they are beneath you. You suck if you do this and you should know that everyone behind you thinks you suck too.
If you get halfway around the supermarket and discover that you don't like the look of that $15 chicken breast after all, don't shove it into the middle of the detergent aisle for someone else to find later.
Do not give your children little bits of food to eat on the way around the supermarket. This called stealing. I don't care if you put the empty bag up to be scanned at the end, it's still stealing.

http://www.goocap.com/2013/09/10-rul...etiquette.html