Twilight.

I have a particular hatred for that series because of how it was introduced to me.

I was working at my local library (during college, probably a decade or so before I became a librarian myself), when our YA librarian passed me a pre-release copy. She was like "people are saying this is going to be the next Harry Potter or something; check it out and tell me what you think."
So I went in completely blind, no preconceptions about it at all since nobody had ever heard of it at the time and I don't think the galley even had an actual blurb on it.
I spent 3/4 of the book waiting for it to be about something, and my report to her reflected that. I thought it was vapid, shallow trash with the most mind-numbing characters and ridiculous plot.

Having seen what it became... I stand by my original opinion.