I discovered for myself and by myself that there is no self to realize - that's the realization I am talking about. It comes as a shattering blow. It hits you like a thunderbolt.
You have invested everything in one basket: self-realization, and in the end suddenly you discover that there is no self to discover, no self to realize; and you say to yourself "What the hell have I been doing all my life?!"
That blasts you.