I've heard that on average we only use 5% of our intellects and 15% of our lung capacities. I like to think that our breathing and thinking are not that shallow.
Anyway, I saw two shared articles on Facebook today that made me see what a what a small fraction of my own physical capabilities I am willing to work to achieve compared to what is achievable.
I'm actually quite satisfied with my own goals. They probably will not change, but I am in awe of the high bar the subjects of the articles linked below have set for themselves. I think it is very likely that they will accomplish them.