I recently popped into the shop for a few bits and pieces. I usually keep a rough running total in my head, and when I was charged it was about a pound more than I was expecting. So I paid, and when I got outside I checked my receipt - it was wrong. I dithered about whether to go back in and mention it, but I did. I showed her where I thought the problem was, so she scanned everything back in and told me it was right. At that point I pointed out that it wasn't by roughly adding up the stuff in my basket, so she called the manager over who sorted it out and refunded my 80p . Should I have left it, either from the start, or when she told me it was right? My logic was if I "buy 2 pizzas for 50p discount" then I'm saying that amount is important to me. However, queue behind me and everyone getting frustrated as I argue over my 80p....WIBU?