In a way, it's reassuring that most animals value sleep as much as we do: we're doing something right if we sleep as much as they do. It is a pity that we haven't developed a way to sleep standing up, like horses do.
I remember a couple of childhood moments I got really confused about sleep. After a day at school, I was ill, so I went to bed at 5 o' clock. When I woke, I saw it was 7 o' clock, and I felt better. I went down and had some breakfast, while everyone else seemed puzzled. It was a while before I realised that it was still evening, and I had assumed it was the following morning! 
It was in spring, so still light outside (and probably dusk, but I thought it was dawn), and I was so confused.
Related to this, from a young age, I found the concept of being blindfolded mental: not so much for sleep, but for games and surprises. It's weird that one person can prevent another person from seeing anything, just like that, and even more weird is being spun round and disorientated, I remember thinking that while playing pin the tail as a child. On one rainy day, when I was nine or ten, I asked my parents to time how long I could stay blindfolded: they agreed as long as I stayed sitting in an armchair, and they used two scarves to cover my eyes. They told me afterwards that they checked carefully that I couldn't see at all, waving their hands in front of me, and shining a torch at my covered eyes to see if I reacted. I wondered why I could only see blackness and not the pattern on the scarf. I remember trying to visualise the room around me, noticing how it "faded" from my memory, and I tried very hard to "see" things. Then suddenly, I found I was seeing things very vividly. I had fallen asleep! After I woke, they asked me to guess how much time had passed. I don't remember what I guessed, but they told me it was an hour and a half.