This point always amuses me. It's common among I'm sure all of us cyclists, to pass a cyclist going t'other way and exchange a smile, wave, greeting. However when it comes to joggers, I've yet to see one smiling or even looking vaguely content.
If jogging is that good for you, why do joggers never appear to be enjoying what they're doing - !
If jogging is that good for you, why do joggers never appear to be enjoying what they're doing - !