Usury

Ancient usury meant the loaning of money (or anything) at interest, and was fiercely proscribed or severely limited by several major religious traditions. As transactions of this sort became imperative for the development of large-scale economies and international trade, however, the definition of what was proscribed morphed into excessive rates of interest (which, as a scalar rather than an absolute notion was susceptible to vagueness and hence upward creep -- consider ruinous 21% credit card rates that are not illegal). It is tempting to blame usury, traditionally a sin, for many of our modern economic inequalities, but though it is certainly an enabling condition, its demise as a social constraint on economic exploitation is at least as much a consequence of present economic arrangements as a cause of them.

It has both downsides and upsides. For example, The fact of easy credit for home buyers puts upward pressure on the cost of homes, thus forcing everyone who wants to own a home to borrow at interest (the rates may be modest, but the amortized outlay over many years is often two or three times the sale price of the home, or more). Those who would have preferred to save their money until they could buy a home outright are mostly priced out of the market by this process, and by the steady march of inflation to which it contributes. On the other hand, the increased price of homes makes it possible for them to be better designed, more energy efficient, etc. than they would otherwise be, since the greater market value of homes permits builders to invest more in their design and construction. Unless this just leads to larger homes (which it sometimes does), it can substantially improve the housing stock, and the quality of life of those connected to the building trades.