“Some humans would do anything to see if it was possible to do it. If you put a large switch in some cave somewhere, with a sign on it saying 'End-of-the-World Switch. PLEASE DO NOT TOUCH', the paint wouldn't even have time to dry.”

“Don't do anything I wouldn't do, if you ever find anything I wouldn't do.”

“Any true wizard, faced with a sign like 'Do not open this door. Really. We mean it. We're not kidding. Opening this door will mean the end of the universe,' would automatically open the door in order to see what all the fuss is about. This made signs rather a waste of time, but at least it meant that when you handed what was left of the wizard to his grieving relatives you could say, as they grasped the jar, 'We told him not to.”

“XXI. But Arnold Bros (est. 1905) said, This is the Sign I give you:XXII. If You Do Not See What You Require, Please Ask.From The Book of Nome, Regulations v. XXI-XXII”

“It's not worth doing something unless someone, somewhere, would much rather you weren't doing it.”

“A lot hinges on the fact that, in most circumstances, people are not allowed to hit you with a mallet. They put up all kinds of visible and invisible signs that say, 'Do not do this' in the hope that it'll work, but if it doesn't, then they shrug, because there is, really, no real mallet at all.”

“Oh, I feel very angry a lot of the time," said Tiffany, "but I just put it away somewhere until I can do something useful with it.”