Philip Stanhope, 4th Earl of Chesterfield

Every man becomes, to a certain degree, what the people he generally converses with are. He catches their air, their manners, and even their way of thinking. If he observes with attention, he will catch them soon, but if he does not, he will at long run contract them insensibly. I know nothing in the world but poetry that is not to be acquired by application and care.