There are certain inalienable elements that every human needs in their environment in order to stay healthy and happy. These elements are green, timeless, and universal.
1. sunlight by day
2. darkness by night
5. meaningful sounds
6. fresh gently moving air
7. thermal comfort within thermal variation (not too hot or cold but some variety)
8. interaction with other humans and other species
9. a sense of safety
10. dynamic synergy among all of the above things
Any design process, whether it is moving furniture around or building a new house, should take these ten points into consideration. To do so will guide you down a path of health and happiness.
Note: the ten points are from Carol Venolia, eco-architect.