because of the way the human eye sees color, it retains a memory of it.. ie, if you stare at a red star shape, for 1 to 3 minutes, and then stare at a white surface, you'll 'see' a green star. (the rods or cones that were excited by the constant visal input of 'red star' remain active even after the stimulation is removed.)

this is why hospitals, (and ER and surgical area's in particular) are painted green.. its restful to the eyes, and after staring at blood, and bleeding, when (dr and nurses) turn away, the 'after image' is lost in the green color of the walls and surgical scrubs.

green, as pastorial color, is also supposed to be a calming color as well.

i like high contrast-- my foyer is deep rich true purple, (its very small) decorated with gold/brass/silver toned picture frames, filled with family and floral photos... the very next room is bright lemon yellow, (just about the perfect opposite on the color wheel) the next room (living room/dining room) is a neutral blueish grey.. the enterance is very exciting, but things soon settle down, to a soft color.

what is amazing is almost no one notices the purple as they come in, they only notice it as they leave. --even people who i have told about the colors-- and who's first reactions is "PURPLE?"-- walk in and 'miss' the color of the entry way!