Personally, I found this volume to be among the best of the discworld books. Not because of the humor - it has its moments, but not very many of them - but because of a number of pretty deep reflections on personal ethics and religion in the scenes with Granny Weatherwax and the Omnian priest, Mightily Oats. Basically, we witness to a man who was religious by habit and education have an experience that makes him "see something holy wherever I look". And we get a peek at the personal hell in which Granny Weatherwax's iron will was (and still is) forged.