I had a rich friend growing up who would often have dinner at our house. One day, I had dinner at hers. The food was amazing, especially this one stinky cheese they had, but her mom and dad kept looking at me strangely. The next day, they sent us a $500 bill for the cheese I had eaten.

Turns out, it was something called Pule cheese which is, like, ridiculously expensive. Still, though, why not just tell me that before I ate it?! I had to use all of my savings to pay them back, and I never saw that friend again.
Ex-friend of my wife, daughter of fairly wealthy business owner. This girl threw a fit at a friendly gathering, complaining about how her father (CEO) had given her (VP of operations-honorary title) a $200K yearly bonus… After she had already prepared her taxes. She was now going to have to go back to her accountant… © Sea_Ganache620 / Reddit