Here is a short list of things that I think would be difficult but not impossible to do:
1. Solving the the Riemann Hypothesis.
2. Talking a socially conservative politician into believing my uterus belongs to me and not god.
3. Finding a solution to the world's starvation problems.
4. Running an Ultramarathon.
5. Getting through the Rig Veda.
6. Winning a wit contest opposing The Oatmeal.
7. Swimming across the English Channel.
8. Becoming fluent in Greenlandic Norse.
9. Playing an instrument as fluidly as Bela Fleck.
Here is an even shorter list of things that would be quite easy to accomplish:
1. Not being an asshole all of the time.
The latter of the two short lists seems a little unreasonable to some, but to me and my relative existence it is completely obtainable state of not-being. Yet for some people it appears they have no other state of being but a douchecopter. I am not really sure if it is an ego problem (given to you buy your parent/s), or if people that are consta-assholes are suffering from some mood disorder, but it is rather unpleasant.