We can see green in more nuances than any other color. In our evolution we always were surrounded by water, plants,sky and fire, blood, poison that indicates in very sharp bright colors as RED or YELLOW. That is the foundation of our understanding of colors. I believe surrounding you are grown up in effect how you react to different colors and obviously the context the color is in.
The bottom line is that you can not get totally scientific approach to how colors affect mood because we all slightly different. But we all do see green in more nuances than any other, that is proven. So when about to blackout the vision eventually collapses to tunnel vision, accompanied by graying or dimming of vision. The brain maight lose the green as the last color?
Colors, like features, follow the changes of the emotions. - Pablo Picasso
http://psychology.about.com/od/sensationandperception/a/colorpsych.htm