Worse is when it is raining and they are leaving. You have a line of people with their trolley barricades standing open mouthed at the idea of water falling from the sky, not wanting to step out into this new unknown hell dimension.
Meanwhile I have walked across the car park in the rain, I'm getting wet, want to do some shopping and the door is completely blocked. On more than one occasion I have stood about a meter away from these statues, counted to 10 then finally said loudly, "do any of you fancy letting me in?". That tends to invoke a zombie grunt and a few shuffle sideways. Sometimes the bravest alphas in the group venture out into the rain, complete with shopping. After watching and finding out they did not melt, the rest slowly follow, only to be replaced by a new group a few minutes later.
Supermarkets, make people forget every concept from the outside world when you are encased within their walls.