Dead Rising.
Starting a new game at level 1, the difficulty curve felt like running headfirst into a brick wall. Sorta like GH3 on expert. After getting up to part with Carlito and dying like 20 times, I put the game on my shelf for awhile. I went back to it a weeks later, leveled up while going for Zombie Genocider, then finally went back into 72 hour mode. It finally seemed fun, and I found I really enjoyed it.