The Adventures of Tom Sawyer

by Mark Twain

He had discovered a great law of human action, without knowing it — namely, that in order to make a man or a boy covet a thing, it is only necessary to make the thing difficult to attain.

Often, the less there is to justify a traditional custom, the harder it is to get rid of it.

to promise not to do a thing is the surest way in the world to make a body want to go and do that very thing.