I’ve said it, your doctor says it, and anyone who’s ever had a bad night’s sleep and felt like death the next day will say it: sleep is absolutely essential to happiness, health, and longevity. On the positive side, there’s nothing quite so pleasurable as a good night’s sleep, from the initial application of one’s head to the pillow, to the insanely vivid dream-visions that descend upon you in the midst of it, to the peerless happiness and boundless energy you feel upon waking. Sleep’s the best, so you want to get it, and get it good.You know it, of course. I harp on it enough. And chances are, you’re doing your part to get good sleep. But what if you can’t? What if sleep is bad, or inadequate, or unfulfilling? What might be causing it? Let’s find out.(This Mark's Daily Apple article was written by Mark Sisson, and is narrated by Brock Armstrong)