Care keeps his watch in every old man’s eye,
And where care lodges, sleep will never lie;
But where unbruised youth with unstuff’d brain
Doth couch his limbs, there golden sleep doth reign.
– William Shakespeare
Romeo and Juliet, Act 2, Scene 3. Friar Laurence personifies care or worry as an uninvited lodger for old people. He says that the old have worries that deny them a peaceful sleep, but young men are meant to be carefree and enjoy long and restful sleep.