>>Only a short timespan, in evolutionary terms, separates us humans from the epoch where we needed to be constantly active during waking hours, simply to survive.

So that's why I'm so restless all the time! Thank you, Dear! I always love to find rational reasons for
behavior.

I will also point out that one way we know this is to look
on television or just open our eyes where we are, and see that there are people all over the world who still have to "be constantly active during waking hours, simply to survive." There are lots of jungle tribes living right beside us, right now. And some of those jungles are in modern cities. Those of us with education and lifestyles that allow us the knowledge to write on this Board, and have the luxury of free time to do it, are extraordinarly fortunate.