Something I find really frustrating is how libraries always (at least in my local area) seem to put all of the fiction in the same section. Maybe I want to go to the science fiction section and browse the covers and be sure I'm getting science fiction! But instead I might grab some slice of life or something and get disappointed when it's not what I'm looking for just because the authors are alphabetically close. Why do these numbered sorting systems exist if nobody uses them? ARE there libraries out there that actually use the dewey decimal system in the fiction section?
In theory, the 800s could be used for fiction, but as most libraries have more novels than non-fiction books that would make it the largest section of the dewey decimal system. It makes sense to separate it, but yeah, it's dumb to lump the entirety of fiction into one alphabetized catalog. The 820s (english literature) is split into poetry, dramas, novels (sorted by publication date), essays, speeches, letters, and satire. 823.08 is for genre fiction, though it's up to the individual libraries what they choose to put there vs in the fiction wing.