Unseen University was much bigger on the inside. Thousands of years as the leading establishment of practical magic in a world where dimensions were largely a matter of chance in any case had left it bulging in places where it shouldn't have places. There were rooms containing rooms which, if you entered them, turned out to contain the room you'd started with, which can be a problem if you are in a conga line.
Terry PratchettYour average witch is not, by nature, a social animal as far as other witches are concerned. There's a conflict of dominant personalities. There's a group of ringleaders without a ring. There's the basic unwritten rule of witchcraft, which is 'Don't do what you will, do what I say.' The natural size of a coven is one. Witches only get together when they can't avoid it.
Terry PratchettHaven't you got any romance in your soul?" said Magrat plaintively. "No," said Granny. "I ain't. And stars don't care what you wish, and magic don't make things better, and no one doesn't get burned who sticks their hand in a fire. If you want to amount to anything as a witch, Magrat Garlick, you got to learn three things. What's real, what's not real, and what's the difference.
Terry Pratchett