Too many to list! Especially now that it's so easy to check out library ebooks. I pick something up and if it starts to annoy me for one reason or another (bad language, stereotype character descriptions, bad dialog...) , within the first 20 or so pages I put it down and move on.
A recent no-finish: Tender is the night, the MR Book Club selection. That one did grab me at first because of great descriptive writing. But the further I got into it the more I hated the characters and I honestly couldn't care less what happened to them!