" On nights such as this, evil deeds are done. And good deeds, of course. But mostly evil, on the whole.   On nights such as this, witches are abroad. Well, not actually abroad. They don’t like the food and you can’t trust the water and the shamans always hog the deckchairs. "

― Terry Pratchett , Wyrd Sisters (Discworld, #6; Witches #2)