Young boys kicking balls about. Tell him to leave it in the car FFS, and don't be surprised and blame him when he knocks stuff off shelves
People putting stuff on different shelves when they change their mind.
People standing so close behind you in the queue you wonder if they're going to start fingering your bum (certain areas of France especially bad for this).
People who probably can't count to ten attempting to use the self service checkout and spending two thirds of their time making lemon faces at the screen. It's supposed to be a FAST lane!
Did I mention: lighthearted 