As I've gotten older I've realized how little I like hard-for-the-sake-of-hard games. I mean, I never really liked stuff like Super Meat Boy, but in general I would push myself into playing the hardest modes because I figured people would think I wasn't trying hard enough. But there came a point where I just said "wait, I'm playing this game to have dumb escapist fun. Why am I frustrating myself over and over just to say I did it?" and I let myself play average-level difficulty. I understand the fun derived from challenge, don't get me wrong, but there are times where I just want to be a god amongst men. Also, in games like Civilization, the computer always cheats and that's not actual challenge.
I still play smash handicapped with all 9s bots though.