I don't play games on hard difficulty usually. I just play at normal or one step above if it is a game I am familiar with, like Halo games need to be played on Heroic at least in my opinion.
The only thing I can point to is playing Halo ODST on Legendary with 2 other people, and it wasn't too bad. It had it moments, but we managed. I remember it as being more fun than frustrating.
Oh and I am on Hell difficulty in Diablo III, which I pick back up from time to time until I get frustrated with it. I also got up to Hell difficulty in Diablo II, and that got crazy from what I can recall, at least with the character I was playing with at the time. (Spearazon build)