Hardness really depends on whether you like something or not, and your previous experience. It's subjective. For a college xc runner, running 5 miles in 35 minutes is "taking it easy", for an average american it's an impossible task,
I think if you find something "hard" you're doing it wrong or setting impossible goals which just lead to frustration and everything becoming harder.
Depends. Some people revel in the frustration of failure. I still remember learning how to unicycle. It was two weeks of constant failure, but in the end I could do what few other people manage.