"Jazzercise is fun; Jazzercise is fun; Jazzercise is fun," ran through my head, convincingly, most of the afternoon, in order to counteract the predominant message my brain was sending my body:  It's Friday, and I'm tired.  After both children's afternoon plans had been solidified, and I was childless for a while, I really had no excuse not to go.

Changing clothes quickly, before I could persuade myself that sitting on the sunlit deck with today's newspaper was my civic responsibility, I considered all of the benefits that a workout would provide.  Ultimately, knowing that a friend was waiting for me was the most powerful motivator of all.  Health and weight be damned, I didn't want to let down my exercise buddy. 

Glad I went, but now I'm done, and I can let my body give in to its original message:  Thank goodness it's Friday, and I'm tired.