Skin doesn't mark where you actually stop, Watts argues: the tidy little self you call "me" is a picture worth questioning, not a settled fact. He calls it a hoax not because you don't exist, but because nothing about you truly ends at the skin: every breath borrows air that was someone else's a minute ago. That's a bigger claim than one morning can settle, but the usable part is smaller: the boundary you defend so hard in traffic is thinner than it feels. Notice one moment today you're defending "me" from something that isn't actually a threat.
The inside information is that yourself as "just little me" who "came into this world" and lives temporarily in a bag of skin is a hoax and a fake. The fact is that because no one thing or feature of this universe is separable from the whole, the only real You, or Self, is the whole.
Alan Watts, The Book: On the Taboo Against Knowing Who You Are, Chapter 3: "How to Be a Genuine Fake"