I think the best thing about coming back into running after taking some time off is the soreness that develops in the muscles in the beginning.
I like the feeling of sore muscles. Especially the quadriceps! Those are my favorite!
When I've been training consistently for awhile it takes a lot for my muscles to get sore. This is due in part to the way I run (slow and steady), and to my muscles becoming stronger and better suited to what I want them to do.
When they are is shape I can feel them. I can feel the fibers firing almost individually as I'm running. I can feel the tightening and loosening of the muscles as I walk or climb stairs or even stretch out in a yawn.
I LOVE that feeling. When I'm out of shape and inactive I miss and crave that connectedness with my body that only months of training can bring around.
But the initial soreness of just starting out is a great reminder of things to come.