What is the worst experience you've had reading a book?

Kevin J. Anderson's Saga of the Seven Suns. I started reading it a long time ago, got about twenty pages in and gave up. Much later, I forgot I had tried, and tried again, and got even fewer pages in when I remembered how it is chock full of the most inane pandering exposition I have ever read. Just a torrent of trite, hackneyed, cliché. I can't understand how it got published, let alone warranted 7 books. Maybe it gets better. I will never find out. I haven't heard much good about the Dune books he co-authored, either.

I should add that I've read Battlefield Earth, and actually enjoyed it. I generally do not have super high standards. If something is entertaining, I'll give it a chance.