[Flat stare and he pinches the bridge between his eyebrows.]

Now you're reminding me of my Pops. He was the strongest man in the world and capable of earthquakes, and five times my size. [All true, even if Marco does hero-worship Whitebeard a lot.]

But even he had to have nurses and takes meds sometimes. Being full grown and an adult means knowing when to use an added resource, not being a stubborn kid about it.