"None are so old as those who have outlived enthusiasm."
American author, poet, philosopher, abolitionist, transcendentalist.
If you can't get up enough blood pressure to vigorously shout "I'm not old," well, then……
One way to keep your personal pot of enthusiasm on the boil is to work real hard at doing the things you want to do, and not doing the other things…I think no one is so busy that she can't decline to do some unappealing or unhealthy or distasteful thing.
I've read Thoreau's Walden and his Civil Disobedience, the first with a reluctant awareness that it wasn't that interesting and the last with gusto, more or less the way Gandhi and Dr. King did….
A minor note to you who are Thoreau fans: this prolific writer and careful thinker didn't pronounce his name like this: Thor-oh' with the accent on the second syllable
He pronounced it like this: Thor'-oh with the accent on the first syllable