I agree that it's hard for some people (managers) to see a relaxed, happy person and believe that they're also totally productive.

I don't blame them either; I feel like the image of overly-caffeinated, stressed-out people is embedded in our collective consciousness as representative of High Productivity and our lizard brains can't seem to be able to reconcile that with the data that is saying "relaxed people who make enough money, are treated well, and have the freedom to live satisfactory lives outside the office will most probably be more productive, focused, and effective at work."