A friend’s husband has a more idiosyncratic transition. He sits on a sofa that faces a built-in bookcase, and, one arm flung over the sofa back, looks at the bookcase. “He calls it ‘staring at the bookcase,’ ” she told me. “He’s not meditating or anything like that, and I can talk to him, but he wants fifteen minutes to stare at the bookcase when he gets home.”