…because I am constantly amused by classification systems. Seriously. How can you not enjoy something that can put something written by Robert Boyle on the same shelf as a biography of John Dee? (Library of Congress Classification does this at one of my libraries.) I’ve also seen books about death shelved right above books about fast food (Dewey Decimal Classification) and, in one very small library, Danielle Steel right next to John Steinbeck (alphabetical).
If someday you’re in a library and you hear someone chuckling in the stacks, it might be me laughing at the weird juxtapositions of books on the shelves.