An ancient proverb summed it up: when a wizard is tired of looking for broken glass in his dinner, it ran, he is tired of life.

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.

Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life.

Unseen University was much bigger on the inside. Thousands of years as the leading establishment of practical magic in a world where dimensions were largely a matter of chance in any case had left it bulging in places where it shouldn't have places. There were rooms containing rooms which, if you entered them, turned out to contain the room you'd started with, which can be a problem if you are in a conga line.

The second mouse gets the cheese!

In ancient times cats were worshipped as gods; they have not forgotten this.