Vain men often give themselves airs of a fashionable profligacy, which, in their hearts, they do not approve of, and of which, perhaps, they are really not guilty. They desire to be praised for what they themselves do not think praise-worthy, and are ashamed of unfashionable virtues which they sometimes practise in secret, and for which they have secretly some degree of real veneration.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“their air and deportment, the fashionable behaviour. Even their vices and follies are fashionable; and the greater part of men are proud to imitate and resemble them in the very qualities which dishonour and degrade them. Vain men often give themselves airs of a fashionable profligacy, which, in their hearts, they do not approve of, and of which, perhaps, they are really not guilty. They desire to be praised for what they themselves do not think praise-worthy, and are ashamed of unfashionable virtues which they sometimes practise in secret, and for which they have secretly some degree of real veneration. There are hypocrites of wealth and greatness, as well as of religion and virtue; and a vain man is as apt to pretend to be what he is not, in the one way, as a cunning man is in the other. He assumes the equipage and splendid way of living of his superiors, without considering that whatever may be praise-worthy in any of these, derives its whole merit and propriety from its suitableness to that situation and fortune which both require and can easily support the expence.” source