In our twenties, when there is still so much time ahead of us, time that seems ample for a hundred indecisions, for a hundred visions and revisions—we draw a card, and we must decide right then and there whether to keep that card and discard the next, or discard the first card and keep the second. And before we know it, the deck has been played out and the decisions we have just made will shape our lives for decades to come.