1) Because I never know which one to choose. I'm afraid that if I pick something too hard, I'll get frustrated with the game, and not finish it. Or get taken out of the flow of the story because I spent so much time trying to beat a certain part of it. Or if I pick something too easy, I'll breeze through the game and never be challenged.

2) Because it trivializes the accomplishment of playing the game. Having a hard time with something? Eh, turn down the difficulty. Ever competed in something against a friend who let you win? Feel good about yourself afterward? I doubt it. You might say, "well don't turn down the difficulty!" but it's not the same. Even just having the option there is a different experience. It's just not as big a deal when you always have that safety net there to catch you.

Plus, there's the issue of bragging rights, too. You used to be able to spend a while beating a game, and be the only one of your friends who had done it. Now they've all beaten it, usually in the first few days of ownership. You struggle through on Insane, and by the time you finish, all proud of yourself, your friends have moved on.

SIGH. Anyway, it's a dumb complaint I suppose, but still, I don't like it. I wish game companies would just balance games reasonably, and give everyone a level playing field. If they must "help" people, I wish they'd do it in game. Checkpoints, tutorials, whatever. Or even including a few cheat codes isn't so bad. Just let it mean something when I say "I beat the game."