What is the most ungrateful anyone has been to you or someone else?

I was prompted to ask this because of this.
I had a girlfriend who was particularly ungrateful for the things people got her. She was poor and couldn’t afford to buy a new dresser so she appealed to her church. Someone donated a beautiful, antique, 5 drawer, tall dresser that had different color wood inlay across the front where the pull handles were. I’d say it was from the 20’s. Almost almost art deco. I thought it was beautiful. She said, “I asked for dresser and this is what they gave me,” and made a grimace of disgust.
I immediately offered to swap her for a plain antique dresser I had refinished. She agreed. So she was finally happy, and I think I got the best end of the deal.

I had an 8 year old tell me that the gift I’d given him for his birthday was stupid. I told him he didn’t need to worry about getting stupid gifts from me again, because I wasn’t going to give him any more gifts. He changed his tune! Now he acts properly grateful when I give him something.