Green tinted with gray is restful and soft. Bright yellow can be warmed with oranges and earth tones such as caramel and brown, or toned down with violet. Yellow with red takes you on a trip to Provence, France. When treated as a neutral, red is warm and comforting. A spicy orange-red hints at the exotic, and blue shows off red's mysterious, dreamy side.
Deeper blues become jewel-like when complemented with reds or greens.
More than that would be sensory overload. I like to have some symmetry. And it's comforting to have one thread of color throughout the room for consistency - even if it's surrounded by chaos. I want them to be knocked off their socks by a burst of elegance. All rights reserved.