All assassins had a full-length mirror in their rooms, because it would be a terrible insult to anyone to kill them when you were badly dressed.
(Pyramids)

Food as an aphrodisiac was not a concept that had ever caught on in Lancre, apart from Nanny Ogg’s famous Carrot and Oyster Pie.*
*Carrots so you can see in the dark, she’d explain, and oysters so’s you’ve got something to look at. (Lords and Ladies)

‘How will I get back?’ he said.
‘Same way you went. We’ll find you and bring you out. With surgical precision.’
Rincewind groaned. He knew what surgical precision meant in Ankh-Morpork. It meant ‘to within an inch or two, accompanied by a lot of screaming, and then they pour hot tar on you just where your leg was.’ (Interesting Times)

'What do you think this is homeopathic warfare? The smaller your side the more likely you are to win?' (Interesting Times)

‘I never look back,’ said Rincewind firmly. ‘One of the first rules of running away is, never look back.’
(Eric)

"'If you ignore the rules people will, half the time, quietly rewrite them so that they don't apply to you."
-Terry Pratchett, Equal Rites

It's fun when it's a plucky heroine ignoring silly social rules, but when it's a fascist grifter ignoring rules that protect democracy and human rights...

Magrat had used a lot of powder to make her face pale and interesting. It combined with the lavishly applied mascara to give the guard the impression that he was looking at two flies that had crashed into a sugar bowl. He found his fingers wanted to make a sign to ward off the evil eyeshadow.
(Wyrd Sisters)

‘Beats me how you fellows remember how to do all this stuff,’ said Ridcully, still watching him with what Ponder considered to be amused interest.
‘Oh, it’s largely intuitive, Archchancellor,’ said Ponder. ‘Obviously you have to spend a lot of time learning it first, though.’
(Hogfather)

‘It’s not what you’ve got that matters, it’s how you’ve got it.’ (Lords and Ladies)

Rincewind had always assumed that the purpose of running away was to be able to run away another day. (Interesting Times)

Who would not rather be a rising ape than a falling angel?

My take on Death of Rats

Attacking a dangerous enemy who isn't there is one of the more attractive forms of warfare ...
(Jingo)

Making history, it turned out, was quite easy. It was what got written down. It was as simple as that.
(Jingo)

When you spend a large part of your life underground, you develop a very literal mind. Dwarfs have no use for metaphor and simile. Rocks are hard, the darkness is dark. Start messing around with descriptions like that and you’re in big trouble, is their motto.
(Guards Guards)

‘Will she live happily ever after?’ he said.
NOT FOREVER. BUT PERHAPS FOR LONG ENOUGH.
(Witches Abroad)

According to the philosopher Ly Tin Wheedle, chaos is found in greatest abundance wherever order is being sought. It always defeats order, because it is better organised. (Interesting Times)

In the jungles of central Klatch there are, indeed, lost kingdoms of mysterious Amazonian princesses who capture male explorers for specifically masculine duties. These are indeed rigorous and exhausting and the luckless victims do not last long.*
*This is because wiring plugs, putting up shelves, sorting out the funny noises in attics and mowing lawns can eventually reduce even the strongest constitution.
(Eric)

A number of religions in Ankh-Morpork still practiced human sacrifice, except that they didn’t really need to practice any more because they had got so good at it. City law said that only condemned criminals should be used, but that was all right because in most of the religions refusing to volunteer for sacrifice was an offence punishable by death.
(Guards Guards)

…she believed in encouraging logical thought and a healthy enquiring mind among the nascent young women in her care, a course of action which is, as far as wisdom is concerned, on a par with going alligator-hunting in a cardboard boat during the sinking season. (Soul Music)