Kermit the frog in his song sings about how "it's not easy being green" but for interior design, green IS an easy color to work with.
I think the biggest reason for this is that green is the main color of nature, The foliage in spring, the mosses, the plankton, the mountainsides, and evergreens. Our eyes are easily adjusted to it and it is pleasing to us.
This is why green is serene. Artwork that incorporates this life-giving color will be timeless and easy to be in.
Go ahead and try a green color scheme in your next room makeover.
Prints in the photo from left to right: Acadia, Shenandoah, Grand Teton