For me, it’s Jude the Obscure. That book is easily the worst book I have ever read, without a single redeeming quality, other than that it finally ends. I only finished it because Far from the Madding Crowd was so damn good.
But really, Jude is the gold standard of awful books, in my opinion.
What’s your so-awful-it-deserves-shelf-space book, if you have one?
Or am I just weird?
Verity by Colleen Hoover. It’ll stay on the bookshelf to make sure I warn people to not read it if they look at my books.