Oh my gosh, "The Scarlet Letter" by Nathaniel Hawthorne for sure. It was so boring!! Almost nothing happens in it, it's mostly the main character's feelings and whatnot. However, I really didn't care about the main character at all since there was no real reason for connecting with her (unless having a kid with someone else when you're married is your kinda thing).
I could go on, but I won't.