giveashitter
That metaphysical mechanical device inside most of us that enables us to care enough about a task or circumstance such that we put forth effective effort to accomplish the task or effect the circumstance. The giveashitter is not infinite, but instead is subject to performance drops due to relative emptiness.
"Dude, I just ain't doing this anymore. My giveashitter's plumb run dry."
Or, "Cry somewhere else Bro, my giveashitter done got a hole in it."
Or, "Cry somewhere else Bro, my giveashitter done got a hole in it."