the current thought is..
the finite-ness of the human body. being tired vs. being exhausted.

its one thing to be exhausted but still having a means of transportation to get from place to place... or home and back into bed. exhaustion on a mountain means you're exhausted and you still have to find your way back. its one thing to push limits but is also another to know how far you're going to do it and to do it so you're not stuck.. on a mountain.

props to Allen for making it to the top and back!