Democracy in America, Volume 3 by Alexis de Tocqueville

The temper of the Americans is vindictive, like that of all serious and reflecting nations. They hardly ever forget an offence, but it is not easy to offend them; and their resentment is as slow to kindle as it is to abate. In aristocratic communities where a small number of persons manage everything, the outward intercourse of men is subject to settled conventional rules. Everyone then thinks he knows exactly what marks of respect or of condescension he ought to display, and none are presumed to be ignorant of the science of etiquette. These usages of the first class in society afterwards serve as a model to all the others; besides which each of the latter lays down a code of its own, to which all its members are bound to conform.

Thus the rules of politeness form a complex system of legislation, which it is difficult to be perfectly master of, but from which it is dangerous for anyone to deviate; so that men are constantly exposed involuntarily to inflict or to receive bitter affronts. But as the distinctions of rank are obliterated, as men differing in education and in birth meet and mingle in the same places of resort, it is almost impossible to agree upon the rules of good breeding. As its laws are uncertain, to disobey them is not a crime, even in the eyes of those who know what they are; men attach more importance to intentions than to forms, and they grow less civil, but at the same time less quarrelsome. There are many little attentions which an American does not care about; he thinks they are not due to him, or he presumes that they are not known to be due: he therefore either does not perceive a rudeness or he forgives it; his manners become less courteous, and his character more plain and masculine.