Zen attacks that one last thing you hold dear: your precious self-conception. It unravels any notion of a freestanding, unconditional "I" and shows it to be a lie, a fabrication, a construction. True realization, the old masters tell us, takes bone-crushing effort. We pulverize the very skeleton of ego—upon which the meat and skin and organs of our illusions hang—and we do it through intense, hurtle-yourself-off-the-cliffs-and-into-the-chasm practice.
Buddhism is not a refuge from life. It is life stripped bare and known most intimately. Zen doesn't make you a "better person." It helps you become fully human. My mentor was no model for how to behave perfectly but for how to experience completely. He never told me how to live my life. He just helped me become alive.
In the Buddhist view, I depend on you for my existence. All things depend on each other, equally. Welcome to the doctrine of dependent origination. It's teeter-totter metaphysics—I arise, you arise; you arise, I arise. Forget about our presumed Maker, the divine machinist in the sky. Take a look at this moment right now. You are you because you are not something else; therefore, what you are not—the chair beneath you, the air in your lungs, these words—births you through an infinity of opposites. It's like the ultimate Dr. Seuss riddle: Without all the things that are not you, who would you be you to? There's no Higher Power in this system to grab on to for support; we are all already supporting each other. Pull a person or people the wrong way and you immediately redefine yourself in light of what you've done to your neighbor.