While many comments bring up the anti-social aspects, I think it interesting to use the thread to think about one of the biggest, and often overlooked personal

While many comments bring up the anti-social aspects, I think it interesting to use the thread to think about one of the biggest, and often overlooked personal productivity attributes: making sure that your body gets a good dose of sleep every day. Good sleep means better cognitive behavior, less accidents, lower bodyfat, lower inflammation, and many other benefits. Sleep has a long list of very positive effects, and I might suggest reading Coren's "The Sleep Thieves" to get a full idea of this. One of the central cores of getting a good night's sleep is "sleep hygiene," which includes having a regular schedule. In other words, get to a schedule and stick to it. Also, exposure to light seems to keep the schedule synced. As many have written, 5pm hardly seems to be reinforcing of the above points.