At dawn, when you have trouble getting out of bed, tell yourself: “I have to go to work—as a human being. What do I have to complain of, if I’m going to do what I was born for—the things I was brought into the world to do? Or is this what I was created for? To huddle under the blankets and stay warm?”
—But it’s nicer here.…
So you were born to feel “nice”? Instead of doing things and experiencing them? Don’t you see the plants, the birds, the ants and spiders and bees going about their individual tasks, putting the world in order, as best they can? And you’re not willing to do your job as a human being? Why aren’t you running to do what your nature demands?
—But we have to sleep sometime.…
Agreed. But nature set a limit on that—as it did on eating and drinking. And you’re over the limit. You’ve had more than enough of that. But not of working. There you’re still below your quota.

From Meditations by Marcus Aurelius