So when I lose a particularly interesting CC game, I feel I have contributed something positive to the outcome. By playing a poor move I have allowed my opponent to set up a particularly brilliant finish. Of course this isn't done deliberately, but at least I can take something away from the game.
Here is an example from a game I finished the other day. White sacrifices a pawn in the opening, in return for a freer position. Around move 16 White offered a draw, but with an extra pawn I felt safe in declining it. Although I was behind in development (look at the bishop on f8), I thought the exchange of queens on move 18 was enough to see me through the difficulties. It turned out that this was probably the big mistake. White's minor pieces jumped into my position and he was even able to ignore my attack on his h1 rook. After 24.Nxe6! I realised that 25.Rd7 was deadly, but by this stage it was too late. 27. ... Bd2 was a '33%' move (2 of his 3 moves gave me chances) but he played with remarkable accuracy right up until the end.