If I don't like the Author's writing style or the setting the book is in, I won't finish reading the book unless there's something I really want to find out.

For example, I hated Twilight.. I hated her writing style, I hated her love triangles but I still finished reading it because I wanted to find out what Bellas power was. Was it worth it?... no not really. But at least I can criticize the books with more authority having read the whole bloody thing.