Just to be mean. We all have thoses mean sides.
Back in the day, I lived in a suburb of NYC. Two doors down from me was another amateur winemaker. When he suggested that we "swap bottles", I thought about it for a while and ended up giving him a bottle of the worst wine I ever made, an oxidized bottle of brown wine that was loaded with mercaptans.
After sampling it, he smiled (knowing his was better) and very politely said "not bad".
The story gets much funnier. We were both going into a winemaking competition. Both he and I entered our best. I ended walking away with eight medals to his two. It clearly bothered him. I am sure that even today he is wondereing how "that swill" that I make was judged better.