Americans seem to pride themselves on sleep deprivation, functioning on little or no sleep for days on end, and still (somehow) making it to work -- but that doesn't mean that it's healthy, or good for your career.
If you have trouble getting through the afternoon without an extra cup of coffee or two, you're either the parent of a small child, an insomniac, or someone who just can't bring himself to go to bed when it's time. All three conditions will wreak havoc on your productivity, but since the last one is under your control, it's the most worth examining, in terms of improving efficiency and job satisfaction. Why do we stay up, when we should go to bed?
Every innovation comes with a price, and not just the one on the sticker. Take the incandescent light bulb, for example. Its invention (by Thomas Edison, Joseph Swan, or at least 22 other folks, depending on whom you ask) allowed us to stay up till all hours of the day and night without burning the actual midnight oil. As a result, people did stay up -- but often for work, not for fun.