Really nice interview in New Scientist last week with evolutionary biologist Marlene Zuk about she calls "paleonostalgia"
"You see this attitude in what can be referred to as "palaeo-nostalgia" – the notion that we were all better off before agriculture, or civilisation or the industrial revolution. It's not to say life has been unmitigatedly getting better. But it's more helpful and accurate to see that all organisms are constantly evolving. There has been no point in our past when we were perfectly adapted to our environment.
I'm not dismissing the idea that you need to look at our evolutionary heritage to think about what's best for us health-wise. But when you start plucking out pieces in an oddly specific way, you can run into trouble."
Smart stuff and worth remembering: it's all too easy to conjure up some time in the reimagined past - on some open grassy savannah when things were ticketyboo and we were perfectly suited to the world in which we live (since when, we've lost something). Things were always in motion.