In color psychology, colors made up of long wavelengths are considered "arousing or warm," whereas colors such as green that have shorter wavelengths are "relaxing or cool." Whereas our eyes must adjust to see colors with longer wavelengths, they don't need to adjust at all to see cool colors.The color green can positively affect thinking, relationships, and physical health. Green is also thought to relieve stress and help heal. You'll often find green in the decor of medical facilities.