Multiple exclamation marks,' he went on, shaking his head, 'are a sure sign of a diseased mind.

He found that he had this sudden desperate longing for the fuming, smoky streets of Ankh-Morpork, which was always at its best in the spring, when the gummy sheen on the turbid waters of the Ankh River had a special iridescence and the eaves were full of birdsong, or at least birds coughing rhythmically

Don't wish, Miss Tick had said. Do things.

And Tiffany knew that if a witch started thinking of anyone as "just" anything, that would be the first step on a well-worn path that could lead to, oh, to poisoned apples, spinning wheels, and a too-small stove... and to pain, and terror, and horror and the darkness.

The disc, being flat, has no real horizon. Any adventurous sailor who got funny ideas from staring at eggs and oranges for too long and set out for the antipodes soon learned that the reason why distant ships sometimes looked as though they were disappearing over the edge of the world was that they were disappearing over the edge of the world.

Ankh-Morpork! Pearl of cities! This is not a completely accurate description, of course — it was not round and shiny — but even its worst enemies would agree that if you had to liken Ankh-Morpork to anything, then it might as well be a piece of rubbish covered with the diseased secretions of a dying mollusc.