Democracy in America, Volume 3 by Alexis de Tocqueville

The first thing which strikes a traveller in the United States is the innumerable multitude of those who seek to throw off their original condition; and the second is the rarity of lofty ambition to be observed in the midst of the universally ambitious stir of society. No Americans are devoid of a yearning desire to rise; but hardly any appear to entertain hopes of great magnitude, or to drive at very lofty aims. All are constantly seeking to acquire property, power, and reputation-few contemplate these things upon a great scale; and this is the more surprising, as nothing is to be discerned in the manners or laws of America to limit desire, or to prevent it from spreading its impulses in every direction. It seems difficult to attribute this singular state of things to the equality of social conditions; for at the instant when that same equality was established in France, the flight of ambition became unbounded.

Nevertheless, I think that the principal cause which may be assigned to this fact is to be found in the social condition and democratic manners of the Americans.