Hard thing about achievement

In order to claim achievement, every individual needs to have goals whose attainment requires effort, and needs to attain success while pursuing the set goal. Our goals can be divided into three groups:

1) Easy goals that can be attained with minimal effort
2) The hard goals which require serious efforts to attain; and
3) Impossible goals that cannot be satisfied, no matter how much effort one makes.
If you look around the world today, most of the impossible things are already done and whatever is left to be done, even a child can do it. It requires incremental thinking, some serious efforts, and consistency in accomplishing it.

I think the biggest disappointment that mankind is facing today to bring the kind of challenges that can enthuse people to think and do hard goals that challenge their capacities and energies. I am into this thinking, if everything worth doing has already been done, why are we so desperately allergic to claim our spot riding on the terrain of achievement?