The Donation Perturbation

I work in a charity bookshop. We accept donations of books, sort them, and set them out for sale. We have many regular customers who buy a few books, read them, return them, and buy more; our books are very cheap. An elderly gentleman I don’t recognise comes in and browses for a few minutes, chooses three books, and approaches the desk.

Me: “Hi. Just these three?”

Customer: “Yes, hold on…”

He hands them to me and rummages in his bag. He pulls out three books that have our price stickers on. I know they are from a few weeks ago as we have a date code on them.

Customer: “I’ve got these to give back to you.”

Me: “Oh, thank you! Okay, your total is £2.25.”

Customer: “I gave you those books back.”

Me: “Yes, thank you. I’ll add them to the donations.”

Customer: “So, we’re okay, then?”

He picks up the three books he chose.

Me: “Um, yeah. Okay, £2.25, please.”

Customer: “No, I gave you three books.”

Me: “Yes, and we appreciate the donation. Did you want to buy these ones?”

Customer: “I gave you three; I’m taking three. Why do you want money?”

Me: “I’m sorry, we’re a bookshop. We raise money for our charity. We do appreciate all donations, but we don’t give books away; we sell them.”

Customer: “So, I can’t take these?”

Me: “You can if you pay £2.25.”

Customer: “I paid for the other three!”

Me: “Yes, but if we just swapped books for free, we’d be a library. Do you want to pay for these or not?”

Customer: “Not!”

And out he stomped.