Nietzsche is someone I became interested in for reasons other than philosophy. I suspect that's the same for a lot of people. In fact, I'm certain that some view him in positively religious context.
For those people, Thus Spake Zarathustra is some kind of bible.
And honestly, I don't know how else to consider it. The man was a thinker, and he had a lot of ideas, not the least of them being the Superman, what he considered to be the future of humanity, the difference between us and this ideal right now being the same that separates us from the rest of the animal kingdom. He was also known for the statement, "God is dead," and that's probably the key transition mark between the Reformation and our modern age of Western skepticism.
The funny thing is, Nietzsche reaches this point not out of a deeply held atheism, but rather believing that humanity has in essence outgrown God. You won't find this more clearly stated than in the dense Modern Testament that is Thus Spake Zarathustra, a book that does everything it can to replicate your basic biblical experience, blending the Old and New Testament (and only obliquely referencing Christianity; in fact, all references are oblique herein), so that only those who are actually considering making a religion out of Nietzsche will consider reading it all the way through.
What's funny is that he doesn't even attempts to hide his frustrations, even repeatedly damning poets, which is ironic, because the style is basically free verse, and there are even passages presented in the form of poems! So that's the kind of thing you can expect if you want to read it for yourself.
I was expecting something different, I guess, especially since this was written only about a century ago. I think Nietzsche went a little crazy. He was definitely brilliant, and I greatly sympathize with his loneliness, but the bottom line is, this is not the product of a mind that was in complete control of itself, or at least not one that wanted to communicate itself clearly. Thankfully, I have another of his books waiting in line, so I will have a basis for comparison.
But this is one good reason why most people have developed an aversion to reading older literature. Or literature in general.