The one positive thing you could say about the bread products around him was that they were probably as edible now as they were on the day they were baked. Forged was a better term. Dwarf bread was made as a meal of last resort and also as a weapon and a currency. Dwarfs were not, as far as Vimes knew, religious in any way, but the way they thought about bread came close.

-- (Terry Pratchett, The Fifth Elephant)

It is said that whosoever the gods wish to destroy, they first make mad. In fact, whosoever the gods wish to destroy, they first hand the equivalent of a stick with a fizzing fuse and Acme Dynamite Company written on the side. It's more interesting, and doesn't take so long.

-- (Terry Pratchett, Soul Music)

"When Mister Safety Catch Is Not On, Mister Crossbow Is Not Your Friend."

-- Detritus learns about weapons safety (Terry Pratchett, Night Watch)

"While I'm still confused and uncertain, it's on a much higher plane, d'you see, and at least I know I'm bewildered about the really fundamental and important facts of the universe." Treatle nodded. "I hadn't looked at it like that," he said, "But you're absolutely right. He's really pushed back the boundaries of ignorance." They both savoured the strange warm glow of being much more ignorant than ordinary people, who were only ignorant of ordinary things.

-- Discworld scientists at work (Terry Pratchett, Equal Rites)

"Zoology, eh? That's a big word, isn't it?" "No, actually it isn't," said Tiffany. "Patronizing is a big word. Zoology is really quite short."

-- (Terry Pratchett, The Wee Free Men)

Many an ancient lord's last words had been, "You can't kill me because I've got magic aaargh."

-- Magic armour is not all it's cracked up to be. (Terry Pratchett, Interesting Times)

In Ghat they believe in vampire watermelons, although folklore is silent about what they believe about vampire watermelons. Possibly they suck back.

-- (Terry Pratchett, Carpe Jugulum)

"Taxation, gentlemen, is very much like dairy farming. The task is to extract the maximum amount of milk with the minimum of moo. And I am afraid to say that these days all I get is moo."

-- (Terry Pratchett, Jingo)

People have believed for hundreds of years that newts in a well mean that the water's fresh and drinkable, and in all that time never asked themselves whether the newts got out to go to the lavatory.

-- (Terry Pratchett, Reaper Man)

People who used magic without knowing what they were doing usually came to a sticky end. All over the entire room, sometimes.

-- (Terry Pratchett, Moving Pictures)

She'd become a governess. It was one of the few jobs a known lady could do. And she'd taken to it well. She'd sworn that if she did indeed ever find herself dancing on rooftops with chimney sweeps she'd beat herself to death with her own umbrella.

-- (Terry Pratchett, Hogfather)