Sleep

Why is it that we need sleep? Why is it required to refresh and recharge us? Why do some people thrive on 8 hours of it and others feel best with 6? Why is it the single most thing that makes me happy? I look forward to going to bed at night and knowing I don't have to wake up to an alarm in the morning. I so love just sleeping until I feel like getting out of bed. Why is that? And why do I feel like I never have enough? Am I addicted to sleeping?