Or: Was für eine Philosophie man wähle, hängt sonach davon ab, was man für ein Mensch ist. [What kind of philosophy one chooses depends on what sort of man one is. -Johann Fichte]
As much as I find for Nietzsche contra omnes on so many issues, it would be dishonest of me to deny that the philosophical is personal here as well. I must acknowledge that part of the attraction that Nietzsche's philosophy holds (and has always held†) for me lies in my own temperament, in what I tried and failed to say here about myself.
Perhaps I can best explain it by analogy to dancing: there are some for whom dancing comes quite naturally, but many of us have to consciously work at it. If we do this for long enough, then the conscious effort of counting beats and planning moves gradually fades into the subconscious, and dancing becomes what we so aptly term "second nature"; but we will never learn as much as fast as those spirits for whom it was "first nature" all along. (Yes, I know that the reality here is a continuum and not a binary opposition; but the differences of degree can be quite significant.)
Well, I once moralized as I danced: as a matter of conscious resolution. This is not to say that my vehemence was ersatz or forced, but rather that my strongest moral sentiments were really intellectual in nature, and only incidentally corresponding to things that do bother most people. I could never really identify with what Leon Kass termed "the wisdom of repugnance", because for me the content of an idea was never repugnant, only its falsity (as I perceived it). Those of you who knew me can verify, if they think about it, that what really offended me in a discussion was not the content of an idea so much as my inability to counter it in a form that would settle the argument. In the absence of a debate, I was quite at home playing devil's advocate or dealing in the most disturbing hypotheticals; but as soon as you took exception to me, I quite naturally assumed that passionate and pained countenance.
My first course in philosophy was in a high school summer program. One day they paired us off, gave us a list of applicants for liver transplants (descriptions like "Billy is six years old and has a condition that will require a new liver every ten years", or "Sarah is a forty-year-old schoolteacher whose liver was injured in a car crash") and told us to rank them in priority by any means we agreed on. I decided that a good way to do this would be to pair them against one another, decide binary preferences, and then total the results; and I started asking my partner whether Billy or Sarah should be ranked higher. I was quite surprised when he looked horrified and told me he couldn't answer, that this was an awful thing to decide. For me it was simple: there had to be an answer, it was just a matter of finding the right criteria. Of course somebody would (hypothetically) die in the end, but that just meant we had to think carefully about our decisions.
For me, the only real moral horror is self-deception, and so anything that led me to suspect I was deceiving myself (or that someone else was doing so) secretly terrified me. That's why, in retrospect, I was so afraid of atheism: because I knew it would mean I was lying to myself about a great many aspects of the cosmos, not simply the existence of a particular God. This moral instinct, the will not to deceive, was stronger than all the social stigma that compose most others' mores. When I despise a philosopher (say, Kant or Sartre or Locke), it is always because I think I have seen in them self-deception of some sort.
And this, of course, is why Nietzsche appeals especially to one of my temperament: because he speaks of observing all moral values from a position of intellectual detachment (at least as a preliminary to making a revaluation of them), pursuing harmful or dangerous truths, becoming aware of the self-deception involved in even this very project— and he truly does these things, more audaciously and thoroughly than anyone else I have read, with a firm grasp on his own psychology (the one needful thing that all the philosophers above leave out of their equations). It is for this that I admire Nietzsche, and verge on that greatest of follies: venerating him as a sage.
For his point is that there are no sages, no mystics, no secret insight into the heart of things. Some can see more clearly than others, but the patterns are there for all to read. The true service to Nietzsche is to incorporate him and then to overcome him, if I am indeed strong enough for that.
†From my first reading of Nietzsche in college, I was awestruck— I often said that I considered him the only sensible philosopher outside of Christianity.