Your parents insisting on paying you some money back for a weekend trip that you bought for them, because you spent such a lot of money...
They are quite frugal and pretty well off, however compared to their pension, I consider myself filthy rich. The money I spent on the gift is not even 20% of what I dump into my mortgage on a monthly basis, in addition to the regular payments. I felt quite embarassed and found it hard to accept it, but also do not want to disclose how "well off" I am. I graciously declined it, joking that that is not how it works with gifts, that I give the gift and it stays given.
Parents love giving you a little extra, that does not stop when you are all grown up. But I want to turn this around and start pampering them, but how do you do that without disclosing you have more money coming in than they do?