I have the power to do the most incredible things.

Every incredible thing is mostly boring from the inside. The record-breaking swim was six thousand lengths in a cold municipal pool. The book was four hundred mornings, most of them going badly.

Incredible is a description applied afterwards, by those who weren't there for the middle. You don't experience it that way while doing it; you experience Tuesday. Which is the good news. The capacity in question isn't some rare substance you either have or don't — it is a tolerance for the unglamorous middle, available to far more of us than ever bother to claim it.