Hey, I've been blogging for a week! No big deal, you say? Yeah, you're right. But somehow, this is fun. Maybe what I had to do was take so much time off, that it became obvious that nothing bad would happen if I stopped "forever". At that point it was no longer an obligation, and hence, it could be fun again... Wow, that makes my brain hurt.
This is related, I think, to the reason I don't like to keep stuff. I am a compulsive thrower-away of things, or lately, a compulsive eBayer-away of things. I like a clean desk, and a clean desktop. I like an empty inbox. I like having zero posts waiting in my aggregator. All of these things - keeping stuff, stuff on my desk, mail in my inbox, are in some sense obligations. Getting rid of them feels good, in the same way that crossing to-dos off my list feels good.
The same thing happens to me with programming. Nothing is more fun than "noodling"; building something new which does something cool, something unexpected, something unplanned. Sitting down at my computer with a task at hand, designed but not yet implemented, is a simple pleasure. At the same time, building something on deadline - or (gasp!) behind deadline - is not fun; it is an obligation. It must be done, and requires the same concentration and creative energy, but the obligation makes it less fun.