A couple of weeks ago, I purchased a complete set of 1947 Vienna fair stamps in blocks of 6 from a relatively new seller on
ebay. These stamps are quite common and easily attained, but I liked them so I bought them for $10.

The blocks were sold as "never hinged", but one block was hinged on the upper 3 stamps. I took the opportunity to try to educate the seller, but made it clear I was still happy with my purchase and had already left positive feedback.
He responded in kind and offered to send me a replacement block at his expense. He also stated " I will also be adding another gift
that I hope you need and will enjoy."
This was that gift.

Obviously, I'm blown away.
I sent him an email, today, asking if it was his intention to send me this Mint (gum disturbance) 1949 Berlin semi-postal souvenir sheet (Scott 9NB3a, Michel, Berlin Block 1) worth $500.
If he wants it back, at least I got to place it next to my singles from the set for a day before I return it :)

Brian