I pretty much feel the same about series that I end up disliking, although I have to wonder why she wouldn't finish the last book in a series. It just seems kind of... well, silly. Especially since (and I know that this is a terrible way to compare books, but) the Narnia books are nowhere near as long as HBP or OotP or GoF.

And, heh. I'm not nearly as far along in Discworld as I could be because I don't have The Next Book. I forget what the next book is at the moment, but I'm like that about reading books in order.