One time I ordered two iced chocolates but the manager made and called out two iced coffees and I was the only one there so they were mine, the cashier had put them through wrong. So I explained and the manager made them correctly but I felt so bad because as I was leaving she started telling the cashier off, I should have looked at the screen when I ordered I did think it was a little cheap at the time.

I'm so awkward so I usually don't even say anything. Another time I was at McDonalds and ordered some chips. As I was waiting a person before me said they had missed out on her chips or something so they looked through all of the orders waiting and gave her her chips and threw away the receipt which I'm guessing was actually mine because I kept on waiting while people after me were called. But I had a train to catch and I was too shy so I just walked off it was so awkward.