I resonate with this, but on the other hand I feel like we live in such a self-centered time. If my cup is overflowing, why not dismiss trivial wants to pour into the cups of others? It provides far more enduring satisfaction from my experience.

I agree. I interpret it as a form of rebellion against the throes of perdition and fighting demons that plague the human condition like greed, anger, etc. The mark makes him aware of the affliction that some men carry.