I have probably been in a situation in which I didn't realize I had too much money until it was so late that it seemed way too annoying to take it back, especially given the amount of money.
But I have to live with myself, so I'm not knowingly walking out with anybody else's money or merchandise.
Once I went to buy fabric for Halloween costumes--specifically, a Harry Potter robe.
In the $2/yard section, there was a thin-but-substantial black knit. I asked the guy, "Is this in the right section? It looks too expensive compared to the other bolts." No, he said, it was the right one. "Are you sure?" I must have pressed him three times. Each time, no, he was sure.
OK, great, I told him I wanted something like 12 yards. As he was getting ready to cut it--hadn't put the scissors to it yet--another guy came buy and they spoke in their language, gesturing to the cloth. I asked what it was about--turns out the stuff was $6 a yard.
"Oh!" I said. "Then only give me 3.5 yards." No, he insisted, he'd quoted me that price, he'd sell it to me for $2.
"But you haven't even cut it yet! I asked you, remember, so I'm not surprised it's more expensive. You shouldn't sell it to me at that low price."
He insisted, I argued. After 3 rounds I gave up. And after I left the store I realized I'd forgotten to look for some other fabric for a knight costume, so I went back in to find him telling someone else about the goof.
I told him again, I'm so sorry, I could return some of the yards and pay the right price. I think he was a bit embarrassed to be caught talking about it, but he again refused.
So I bought vinyl fabric to make pants for a knight costume, and I make that store my first stop every time I go to the fabric district.
I'll say, even though I behaved completely honorably and perhaps had the right to feel proud of my "steal," it did feel a bit like a steal, with no quote marks. Kidna ruined the fun of the find.
But I made a ton of costumes out of that fabric, and he got a lot of goodwill. I don't know if he got $12 worth of future profits out of it!