Christmas is not so much the season of giving but of trading. Commerce is nearer our nature than charity, so we strive to exchange gifts of precisely equal value. We resent the friend whose gift is unexpected, forcing a late run to the mall to reciprocate. Like accountants, we must settle the books and rid our balance sheet of debt.
Often, lest we surprise each other with unwanted gifts, we tell each other what we would like: in brief, we run each other's errands.
Since, in exchanging presents, everyone's net gain is null, I prefer the more efficient gift of not giving.