When you wake up, what's the first thing you think about? What's the last thing you think about before you fall asleep? Are they the same?
If I think at all when I wake up (which is debatable), it would be something like: "Aww. Phil's cute when he sleeps. I love him so much. Where is Miss Hobbes? Oh, there she is meowing at my feet and making me trip over her. Stupid cat. I need tea."
When I fall asleep, I tend to think about what I have to do the next day, or I tell myself stories that I plan to start writing the next day and end up not having time to do.