I hate the games I lose because there is usually (9 times out of 10) nothing I can do to affect the outcome.
I hate the games I win because the win mostly comes down to how bad the other team is, or a superstar on my team, and I was mostly a spectator.
The games I enjoy are where it is a hard fought battle with decent teamwork that pushes me to my limits and beyond, and in those cases I don't care if I win or lose.
I've had 20 game winning streaks, 20 game losing streaks. Between the match making, smurf accounts, and weird balancing issues, it's very hard to know what is dictating the outcome. The psychology is so destructive if you place any value on the outcome.