For me, working in archery, it's when customers say "you sent me a left-hand bow when I ordered a right-hand bow".
99 times out of 100, they got the correct item, they just didn't realise.
Knowing with almost absolute certainty that they did receive the correct item, before even seeing what they received, can be difficult to hide. Being in customer service though, I can't just say "you're wrong, send me a photo and I'll prove it".
I have to say "very sorry for this mistake, can you send through a photo so we can figure out what mistake we made?"
That way, the customer doesn't feel attacked or invalidated, but they still have to send through a photo. It's at that point I say "sorry about the confusion, but that is the correct item". All the while thinking "I fucking knew it, goddamn idiots are everywhere".
That specific instance happens at least once a week, but is definitely niche for retail stores dealing with archery gear.
It got me wondering though, do other retail stores get stuff like this? Do toy stores have that one toy that confuses people? Do game stores have that one accessory that customers can't figure out? If you have any similar experiences, I'd like to hear them.
People who find something on the clearance shelf but it doesn't have a clearance sticker on it. They don't seem to understand that anyone can put anything anywhere they feel like it, but without a clearance sticker it is not clearance. And it's not false advertising either.