Stupid Customer

A man comes in to return a $200 rug. His receipt says he bought the rug and one $4 item. (He is only returning the rug.) He has also paid partial payment on his amex ($151) and $62 on store credit.

Me: Hello how are you? The rug didn't work out?
Customer: No, just wrong size.
Me: Okay well I can put $151 back on to your amex (slide card) and $58 is on this store credit for you.
The receipt prints and I hand him his cards.
Me: If you could please sign the top line and you are all set.
The customer has a confused look on his face...
Customer: I don’t understand why I only get $58 on this store credit... I should have $62.
I look at his receipt....
Me: Well it looks like you also bought a $4 item (that you did not return), so that is why you aren’t getting that extra $4.
Now the customer looks even more confused...
Customer: I’m a mathematician and this doesn’t make any sense to me!
I think he might be kidding, but realize he is not.
Me: Well you only returned the rug so I gave you back the $151 to your amex and the rest of it is $58 because you didn’t return the $4 item.......$58 plus $4 is $62. Did you want to return that $4 item?
The Customer is now doing paper and pencil math...
Customer: No, but I should have $62 on this card! Do you have a calculator?
Me: Not up here, but I can go get one for you.
Customer: NO never mind! You need that money more than I do! I’m never shopping here again!

Ah, I love my job.