100 pages is generous. If I'm dreading picking it up by page 50, I'm done. The sunk cost of pages already read isn't a reason to keep suffering. Some books just aren't for you — no shame in that.
Faulkner in this case — the original post was someone stuck on "As I Lay Dying". Genuinely one of those books where the prose fights you the whole way. Some literary classics are just hard work for not enough payoff.