Idk if it’s quite a “classic,” but Bram Stoker’s Dracula. The first three chapters were fine, but the ensuing rest of the book was such a bore. All the male characters could’ve been one for all I care outside of Van Helsing, the females were written hilariously helpless (Mina not as much but everyone was shocked when she was competent), and the constant soliloquizing I found tiresome. A lot of people really like it but it was just a chore for me to finish

Other people have mentioned great books, I’ll toss in most books written by Toni Morrison. I’ve read Beloved, Song of Solomon, and am reading The Bluest Eye, and her prose is addicting to read. Every sentence seems to just dance off the page. It’s truly astounding how she can write so beautifully about such dark topics.