Sometimes, when people are paying with cash, they'll give me extra change so they get less change back.
For example, if someone's total is $10.60 but the only change they have on them is three quarters, they can give me $10.75. This means I'll give them back a dime and a nickel. If they had just given me $11, I would have given them a quarter, a dime and a nickel. So they got rid of three coins and got two coins back instead of getting rid of no coins and getting three coins back.
People also like to have bigger bills, so if their total is $10.60, they'll give me $21 instead of just handing me a $20 bill so they can get a $10 bill back.
This is a perfectly normal thing to do, and I actually love it when people do this because I hate counting out change. I would much rather wait for you to find exact change or to find whatever change you want to give me than count out 98 cents.
But sometimes people are so silly. Sometimes, when they try to give me change to improve their change, they do it wrong and I end up having to give them more change than makes sense.
I wouldn't say this happens often, but I have had it happen several times.
Here's the thing: if this happens and you apologize or even just say something like, "Oh...oops," it's not a big deal. I understand getting confused about math things.
But one time, this girl looks at me like I'm crazy and says, "I gave you that because I wanted to just get a quarter back."
How am I supposed to answer this? It was too quick to figure out how much she would have needed to give me and tell her that, and saying, "Sorry you gave me the wrong change for that" sounds rude.
I think I just said something like, "Oh sorry about that, here's your receipt," because there wasn't anything I could do about it at that point anyway. The cash drawer was closed and I had given her the correct amount of change back.
Sorry you're bad at math?