I say, intellectual labor can be more emotionally exhausting than digging and moving hundreds of pounds of dirt to set a foundation, or hand-removing a tree stump.
It is hard to turn around, glance over your shoulder, and survey in all directions. Wherever you look, the rest is concealed.
And so you put seemingly endless hours into building up a robust intellectual framework, only to discover, crap, I see so much, but now what about all that other stuff that has passed out of my view?
And then you turn to that other stuff, and sure enough, patiently, sneakily, everything built deteriorates and shrinks back.