I think the worst part of not being able to sleep but being tired is the fact that the mind spins endlessly. Not only that, I get super emotional late, late at night when I should be sleeping. I go over recent experiences and mangify their meaning in my mind. Every rejection is a dagger to the heart. Everything good thing is a triumph to be savored. Unfriend me on LJ - you hate me because I'm obviously boring. Decline a dinner invite - you don't care about me because obviously I'm not important. Give me an unexpected call and you love me, you really, really love me! Agree that my opinion was the correct one and I am obviously all that and icing, too.
I dislike such extremes but I can't seem to help them when it's this time of night, I'm tired but I can't sleep. So, I go to distract myself. Online games, books and TV. Of course, I don't feel like reading, there's "nothing" on TV and online games bore me. I think, being in a lack of sleep study might be a really bad thing for me and the researchers in the end, no matter how interesting it in while it is going on.