To this WaPo post, "This chart might make you feel better about American inequality":

What this [chart is] telling us is that in India and Brazil, the poorest people are among the poorest people in the entire world, whereas the richest people are either middle-class, globally speaking, as is the case in India, or are for-real rich, as is the case in India. But if you’re in Russia and especially if you’re in the United States, the mere fact that you live there means that you are not (with some exceptions) poor in the global sense. The bottom fifth of Americans are still well above the middle of the world income distribution.

I offer this passage, which is in the final and dullest chapter (Taxes) of Adam Smith's An Inquiry into the Nature and Causes of the Wealth of Nations:

By necessaries I understand, not only the commodities which are indispensibly necessary for the support of life, but whatever the custom of the country renders it indecent for creditable people, even of the lowest order, to be without. A linen shirt, for example, is, strictly speaking, not a necessary of life. The Greeks and Romans lived, I suppose, very comfortably, though they had no linen. But in the present times, through the greater part of Europe, a creditable day-labourer would be ashamed to appear in public without a linen shirt, the want of which would be supposed to denote that disgraceful degree of poverty, which, it is presumed, nobody can well fall into without extreme bad conduct. Custom, in the same manner, has rendered leather shoes a necessary of life in England.