I have issues with book series. It is fine if a story is complete at teh end of each book, but if they leave you with clif hangers and unresolved issues, then I feel obligated to read the next book een if the series isn't that great in itself. I prefer series where each book is more like whole new adventures with known characters, where it doesn't matter if you read them in the Chronological order or not.
Dune started out well , but then introduced a tremendous number of seemingly disconnected pointless characters , and I lost interest , then it began tying them together , and at the very end , it began to make sense again , in a very unexpected way . Then I saw the movie .