(We were having a sale: 4 bags of liquorish for $12. I ring each bag up individually, and it shows up as $3 a bag.)

Customer: “I don’t want those if they come up to $3 a bag. It said they were 4 for $12.”

Me: “But if you’re buying 4, at $3 a piece, that’s $12.”

Customer: “No, that’s $3 a bag. I want all 4 for $12!”

Me: “Okay…”

Related:
Math Is Your Friend, Part 2
Math Is Your Friend