I'm one of those annoying people who can wake up in the morning with a smile on my face so I usually try to work out first thing, unless I've got an early meeting to attend. I think I feel better all day long when I've started out my day the right way. It's like it sets the tone of the day or something.
Overeater, I saw in another thread that you got in a workout this morning and now you feel all pumped up. I'll bet your workout has something to do with it.