Allan Bloom describes the spot exactly:
“This is where what I called the bottomless or fathomless self, the last version of the self, makes its appearance. Id, Nietzsche named it. The id mocks the ego when a man says, “It occurred to me.” The sovereign consciousness waits on something down below, which sends up its food for thought. The difference between his version and the others is that they began from a common experience, more or less immediately accessible, that all men share, which establishes, if only intersubjectively, a common humanity that can be called human nature. Fear of violent death and desire for comfortable self-preservation were the first stop on the way down. Everybody knows them, and we can recognize one another in them. The next stop was the sweet sentiment of existence, no longer immediately accessible to civilized man but recoverable by him. When under its spell, we can with certainty say to ourselves, “This is what I really am, what I live for,” with the further conviction that the same must be so for all other men. This, allied with a vague, generalized compassion, makes us a species and gives us guidance. At the next stop there turns out to be no stop, and the descent is breathtaking. If one finds anything at all, it is strictly one’s own, what Nietzsche calls one’s fatum, a stubborn, strong ass that has nothing to say for itself other than that it is. One finds, at best, oneself; and it is incommunicable and isolates each from all others, rather than uniting them. Only the rarest individuals find their own stopping point from which they can move the world. They are, literally, profound.”
[The Closing of the American Mind, with added emphasis in bold.]
I have also known such a “This is what I really am, what I live for”; but it was not like that which Jenny describes. I even had the further conviction that the same must be so for all other men.
Now I still feel this is what I live for, but I feel no need to generalize from my individual case. Whoever recognizes his own in mine, let him take it.