So, what happened?

At the end of every year, one has the same conversations. "I can't believe it's nearly Christmas! Wasn't it March only a few days ago?" What happened, we wonder, to the spacious durations of yesteryear, when twelve months seemed an eternity?My theory is that mischievous elves in the eleventh dimension are cranking up the time machine. Either that, or the expanding universe really is speeding up.