Wuthering Heights.

The atmosphere was wonderful (gothic!), and I was keen on learning how the characters would change and grow over time.

They didn't. By the end, Catherine was still an insufferable child, but in adult form, and so was Heathcliff. But he tacked on 'abusive monster' to his roster of unlovable traits. It felt like I had nobody to root for until the last quarter or less of the story.

That is a long time to wait to have a character who didn't create their own misery, blame everyone else for it, and hurt everyone around them. And that be simply who they were.

(Edit: to clarify, Heathcliff had a raw deal in his early life and was mistreated by people while he grew up. He was primed to be a character you could empathize with. But he was so mean, so cruel, so deliberately monstrous that it overcame how sorry I felt for him, and the grace I might have given him.)

I finished the book and it took me a good few seconds to talk myself out of forcefully throwing it into the trash.