I watched a disabled man trundle a trolley with more than 12 items up to the 12 & under aisle in a local supermarket this week.
I watched and wondered who would tap him on the shoulder, and say "excuse me mate!".
No one did. Supermarket queues are a great place for people watching, I find.
I once observed an angry woman swear loudly at the news her favourite cigarettes were out of stock. After multiple F bombs, she spat a "what the f**** are you looking at" towards a young checkout operator, who had glanced at our special princess after the fourth or fifth eff-word.
The good outweighs the bad though, when it comes to supermarket aisle entertainment.