Stuart Walpole has a good article on Gamedev.net about designing games for folks with little gaming time. I agree wholeheartedly with his points. An excerpt:
I have better things to do than attempt the same mis-timed jump again and again: Why oh why have jumping “puzzles” not died the death they richly deserve? There’s nothing that quite kills pacing like reloading the same quicksave (or better yet, being returned to your last save point) until you beat a tedious activity through sheer trial and error.
What, exactly, is my incentive for continuing to waste my precious time in this situation?
My own incentive is I refuse to be defeated by something a six-year-old could best e.g. Super Frickin’ Mario Brothers 3.