The notion that every exchange must be preceded by a weighing of losses and gains and at least eventuate in an equilibrating of the two is one of those rationalistic axioms that are so utterly unpsychological. This would require an objectivity regarding one's own desires which the kinds of psychic constitutions to which we have just alluded do not sustain. The undeveloped or prepossessed mind does not gain enough detachment from the momentary surging of his interest to make a comparison. At the moment he only wants the one thing; giving up something else therefore does not have the effect of being a detraction from the satisfaction he seeks. In other words, it does not count as a price.

Georg Simmel, on individuality and social…, loc. 253