Evil in general does not sleep, and therefore doesn't see why anyone else should.

Divers alarums and excursions', she read, uncertainly. 'That means lots of terrible happenings, said Magrat. 'You always put that in plays.' Alarums and what?', said Nanny Ogg, who hadn't been listening. Excursions', said Magrat patienly. Oh.' Nanny Ogg brightened a bit. 'The seaside would be nice,' she said. Oh do shut up, Gytha,' said Granny Weatherwax. 'They're not for you. They're only for divers, like it says. Probably so they can recover from all them alarums.

After a while, another voice said: One, two, three, four- And the universe came into being. It was wrong to call it a big bang. That would just be noise, and all that noise could create is more noise and a cosmos full of random particles. Matter exploded into being, apparently as chaos, but in fact as a chord. The ultimate power chord.

Knowing how bad you could be is a great encouragement to being good.

If you had enough money, you could hardly commit crimes at all. You just perpetrated amusing little peccadilloes.

You had to hand it to the Patrician, he admitted grudgingly. If you didn't, he sent men to come and take it away.

...it is well known that a vital ingredient of success is not knowing that what you're attempting can't be done.