Kerbal Space Program is the most fun I've ever had failing. And man oh man, did I fail – over and over again. It's part of Kerbal's experimental nature. By the time I finally built a rocket that achieved successful orbit, I had failed so many times that in almost any other game I would have given up completely. But that's where the genius of Kerbal really is: hard work pays off, and once I was able to determine the cause of my failures, be it staging woes, or my nose pitching violently at 1000 meters, every successful launch was a thing of beauty.