Reading this book can feel like losing your sanity a little at a time. It is physically a book, but it's not really a book like you would expect it to be when you approach it as a coherent story. In fact you can probably read it a number ways and take away totally different impressions, which I guess is true of a lot of books but it's surely a hell of a lot more true of this one.
I think people probably read it for the same reasons people climb mountains and jump out of airplanes.