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?
In the early 2000s I read Loop Group by Larry McMurtry and it was so bad I felt certain that either he didn’t really write it or he turned in the first draft.