Whether you are an expert in a striking-based art—boxing, karate, tae kwon do, etc.—or just naturally tough, a return to childlike humility awaits you: Simply step onto the mat with a BJJ black belt. There are few experiences as startling as being effortlessly controlled by someone your size or smaller and, despite your full resistance, placed in a choke hold, an arm lock, or some other “submission.” A few minutes of this and, whatever your previous training, your incompetence will become so glaring and intolerable that you will want to learn whatever this person has to teach. Empowerment begins only moments later, when you are shown how to escape the various traps that were set for you—and to set them yourself. Each increment of knowledge imparted in this way is so satisfying—and one’s ignorance at every stage so consequential—that the process of learning BJJ can become remarkably addictive. I have never experienced anything quite like it.

The Pleasures of Drowning : Sam Harris

This is extraordinarily well put.