Another problem is that you’re assuming you need the same number of hours of sleep every night, which is a false assumption. Your sleep needs vary from

Another problem is that you’re assuming you need the same number of hours of sleep every night, which is a false assumption. Your sleep needs vary from day to day. Dear lord. No joke; this blew my mind. I think I have intuitively understood this for ages, but I never really consciously stepped back and thought about it before. It's so important, because it's deceptively easy to get a complex about sleep times: "Oh God. I'm only going to get 6 hours of sleep tonight! Noooo!" Well... for many (me included) it's not such a giant catastrophe if you don't do it all the time. Owning that, both intellectually & emotionally, is a pretty big deal.