Begin it well and serenely and with too high a spirit to be encumbered with your old nonsense.

I loved school, where I excelled for a short time, and now my golden-haired gap-toothed daughter, who is 9, loves it, too. She tolerates weekends pretty well but on Monday she is all eagerness, leaning forward on tiptoes with that heightened sense of possibility that is the basic component of cheerfulness, which is the secret of the good life.

Cheerfulness isn't the same as happiness. You can't always be happy. Or satisfied. But a cheerful outlook is always possible. Ancient people in wheelchairs in nursing homes, their minds in ruins like the Parthenon, nonetheless beam at the stranger out of lifelong habit, putting the best possible face on things, even during great vacancy.

I turned 65 last month, which is about as festive as walking into a brick wall, but I'm okay now. And when I look back on my messy life with all the wrong turns and failures and days I wish I could rewrite, and then I think of the shining child whose picture is on my cellphone, the door to the past closes. You cannot possibly regret anything in a chain of events that led to her existence. So you turn to the future. 

As Emerson said, "This time, like all times, is a very good one, if we but know what to do with it. ... Finish each day and be done with it. You have done what you could. Some blunders and absurdities no doubt crept in; forget them as soon as you can. Tomorrow is a new day; begin it well and serenely and with too high a spirit to be encumbered with your old nonsense."

In other words, cheer up.