From   u/Polvoroni Tales From Retail:

I work at an arts and crafts store. A customer comes in with a receipt of maybe 12 items, saying that they purchased a "black marker" but accidentally left it in the store. No one left a marker up front, so another associate asks them to show the item on the floor; they point out a $4.99 acrylic marker. We get the item number, but it doesn't match anything on their receipt.

I suggest that they might have the wrong receipt, they suggest otherwise. After a long exchange about why I can't just give them a marker without any proof that they paid for it, they relent.

C: "It's fine. I don't want the marker anymore. I'll just return it for a refund."

Me: "I can't do that. It's not on the receipt and you don't have the item."

They demand I go down the list of items, explaining what each one is. The only one I can't describe is a seasonal item with a SKU number that turns up blank. It's $19.95 and some sort of paint set.

C: "That must be the marker."

Me: "It's not the same marker that you pointed out on the floor. It's a paint set."

C: "Yeah, the actual marker was sold out. (????) That must be the one I left here."

Me: "We don't sell any markers for that price..."

C: "Yeah the marker was sold out!"

The store manager took over the transaction and ultimately told the customer the same thing. After they left all huffy and defeated, my SM and I just stood there dumbfounded. Honestly, they spoke with such conviction that I feel like I might be missing something...

--u/Polvoroni