I think I went into mourning at the end of the series. It was very sad.
I think this is one of those books were you see the characters grow and challenge themselves to be better, and then when it ends the way it does you feel so sad. It's like they aren't really able to (truly) apply all that they learnt.
Interesting take on Kitty being old and alone. I never looked at things that way before.....that is indeed sad. I wonder if he ended it that way so that he won't be forced to continue the series? Even if he did write a prequel.