What was the worst book you’ve ever read?

Probably not the worst I ever read, but whenever a question such as this comes up my mind immediately goes to one of the Tarot books by Piers Anthony. I don't remember which one, it was just in a pile of books people left in a dorm one time and I had nothing to read. I finished it, but I can't tell you anything about it other than the vague recollection that I hated it.