Terry Pratchett on Life, Marriage, And Everything

A marriage is always made up of two people who are prepared to swear that only the other one snores.
Only in our dreams are we free. The rest of the time we need wages.
One of the universal rules of happiness is: always be wary of any helpful item that weighs less than its operating manual.
He'd noticed that sex bore some resemblance to cookery: It fascinated people, they sometimes bought books full of complicated recipes and interesting pictures, and sometimes when they were hungry they created vast banquets in their imagination.
“Wen considered the nature of time and understood that the universe is, instant by instant, re-created anew. Therefore, he understood, there is, in truth, no Past, only a memory of the Past. Blink your eyes, and the world you see next did not exist when you closed them. Therefore, he said, the only appropriate state of the mind is surprise. The only appropriate state of the heart is joy. The sky you see now, you have never seen before. The perfect moment is now. Be glad of it.” 
Sergeant Colon owed thirty years of happy marriage to the fact that Mrs. Colon worked all day and Sargent Colon worked all night. They communicated by means of notes. They had three grown-up children, all born, Vimes had assumed, as a result of extremely persuasive handwriting.