Back when Mary Stewart's Arthurian Saga was being released, I stopped and never did read the fourth book (The Wicked Day). I don't read lots of fantasy and only knew the most basic details of the legend of Arthur. If I'm remembering who's who correctly, Stewart made Mordred so sympathetic, I couldn't stand to read the next step (where he turns into the villain of the piece).
I'm also pretty sure I have a few books that are 1 or 2 in a trilogy that I never did read because I was collecting them to read the entire series at a go, and I heard it ended up going in a direction I knew I wouldn't have liked.
