I have a couple of really weird experiences.
The first one. It was over 10 years ago. I was food shopping at Tesco. We all know how stressed you feel when you have a trolley full and you are struggling with bags etc. I was just about to walk away and a lady behind me shouted. "Excuse Me, I think you have just been overcharged". She then explained further. LOLOLOL.
You ready for Wally of the week? You have just been charged £8.60 for 3 pack of chocolate. It was in fact the case, she had seen it. Me, I would never have known, as I never (embarrassed cos I still dont) check receipts.
On the other occasion, I was in M&S with a mass of lingerie bits and pieces. I thought I had been undercharged. I told them. She looked in the bag and counted and said, No, it is right. I asked, again, are you sure. She looked again and said yes. So, I came home, when I get home, she had in actual fact missed an item. I felt really bad about it. I always feel that staff made be held responsible etc. and it worries me.