It's about a tie between these two:
Jane Eyre by Charlotte Bronte: You know what this book is? Feminist propaganda, plain and simple. I sure seemed to have read a lot of crap like this, but this is the Crap Queen. It's a Victorian romance novel, of course.
The Sound and the Fury by William Faulkner: At least you could READ Jane Eyre. This one hardly counts as a book. The plot is basically just following the lives of various members of the degenerate southern family the Compsons, so in other words nothing interesting at all happens. However, Faulkner must have thought that idea wasn't terrible enough, so instead of just writing it properly he has to shift perspectives to different scenes every few sentences, making it damn near impossible to follow. You could be reading this one scene and all of the sudden, bam, it shifts to a completely different scene about ten years previously, then after a few sentences shifts back.