Rolling stones and moss retention

As I observed the many moss covered rocks during my Valais hike, the saying a rolling stone gathers no moss jumped into my head. I wondered if always running is a good thing or not. Maybe it is better to gather moss and admire the colour and texture and to nurture this life form. And of course, there may be stones that want to roll and stones that don’t. If all stones rolled where would moss live? So here’s to the stones that roll and the stones that don’t.