What makes a run great?

I had such a great run tonight. It was short, and it was really hot outside. I haven't bought any body glide yet, so there was a little aquaphor adventure. I ran in nike tempo shorts, which, no doubt, show more of my still-squishy legs than I would like. But I listened to the first episode of the runnerslounge.com getting started podcast. I made a point to smile from ear to ear for no reason the whole run. I did NOT wear my garmin. I just ran.

 I wasn't running to lose weight.

 I wasn't running to accomplish a training goal.

 I wasn't running cause I had to.

 I ran cause it feels good to turn my head off, and I ran because I can. I feel so much better. :)

 What makes a good run/workout for you?