Why should the man, whom nobody thinks it worth while to look at, be very anxious about the manner in which he holds up his head, or disposes of his arms while he walks through a room? He is occupied surely with a very superfluous attention, and with an attention too that marks a sense of his own importance, which no other mortal can go along with.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“Politeness is so much the virtue of the great, that it will do little honour to any body but themselves. The coxcomb,12 who imitates their manner, and affects to be eminent by the superior propriety of his ordinary behaviour, is rewarded with a double share of contempt for his folly and presumption. Why should the man, whom nobody thinks it worth while to look at, be very anxious about the manner in which he holds up his head, or disposes of his arms while he walks through a room? He is occupied surely with a very superfluous attention, and with an attention too that marks a sense of his own importance, which no other mortal can go along with. The most perfect modesty and plainness, joined to as much negligence as is consistent with the respect due to the company, ought to be the chief characteristics of the behaviour of a private man. If ever he hopes to distinguish himself, it must be by more important virtues.” source