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.
If you want to be clinical about that, it's true.
However, in my family we usually say something like "Oh, I'd like a new bathrobe" and the choice is down to the giver. So there's still an element of thinking about the person, and their tastes, while making sure it's in the right ballpark. And then there's still care put into wrapping it, and the enjoyment of all sitting together for a period on Christmas morning, opening the presents, sipping a glass of wine, chatting, breaking open the chocolates....
Even when it's something very specific, (Like this year, I asked my sister for a specific CD), it's often something that we wouldn't actually get round to buying for ourselves. Christmas is a prompt to treat ourselves, by proxy.
Also, we all enjoy finding little extra surprises for each other, over and above the 'known' gifts.
I love giving presents, I find I have to stop myself from adding more and more to the list, especially for those I know and love the most. I wouldn't much care if I got nothing back, as long as I knew they were made happy by what I give them.