Is Christmas Inefficient?

McArdle defends the gift-giving holiday:

Having another person buy you a gift stretches your consumption possibilities beyond the limits of your own imagination.  Yes, often they will buy you something you don't like as much as the thing you would have bought.  On the other hand, sometimes they'll buy you something that you like even better than the thing you bought with your own money.  Last year my in-laws got us a motion-activated soap dispenser which turned out to be the absolute perfect thing for our powder room.  I'd never have bought it myself, but I know I like it better than whatever we'd have bought if they'd given us cash instead.