I don't find it fun to play a game that I have pretty much already lost. I prefer the opponent to just go ahead and deliver the checkmate rather than chase me around the board.
I'm also bad about giving in easily when it seems to get tough. I need to work on that.
It hurts to know that there is no way you can win in a game. So, to end their suffering people opt to click the resign button. Besides they can play another game.