Benjamin Franklin nailed it when he said, "Fatigue is the best pillow." True story, Benny. There's nothing like pushing your body so far past exhaustion that you'd willingly, even longingly, take a nap on a concrete slab.
Earlier this month, I found myself on the verge of throwing up from exhaustion as I did jumping jacks in the middle of Bryant Park in Manhattan. It was sometime after 5:00 a.m. and the sun had yet to rise.