The sadness because it is over. Yeah, it's better to go out at the top of your game than to drag on forever, something that has been proved by more shows than I can count. So I'm not complaining, really; the creators had a vision and they held to it and it worked beautifully. But that doesn't stop me from being wistful.
So when is the complete series coming out on DVD again, so I can watch it all once more from the top?