It's also cool to notice that most "earthy colors" (browns, olive green, dark greens, etc) often have a combination of warm & cool colors within them. And then when you combine any two complimentary colors - you get different shades of brown/grey. Like adding two rainbow/celestial colors together brings you more "down to earth" - sometimes anyway. Rainbows blending into the earth... :) I know- there are exceptions to this - but it sounds cool anyway.