It is interesting that different cultures interpret things so different. This is the case with the gray color, which in the west we associate with the fog, the sadness, but yet in the East is the color that denoting wisdom, peace and serenity.
Grey is a color that has a variety of shades and tones. From the soft dark charcoal pearl, the range is very wide. So is opening an important gap in decor. If we use it in fabrics or paint, the textures can get to get infinite combinations.
But the most surprising thing about this color is the feeling that we can transmit as combine with one color or another, for all blends. For example with roses objects will create a romantic atmosphere, provided they are both of the same intensity.
If you are looking for is to fill a stay of joy, then we will choose to yellow or green in your options more alive, which released luminosity. If we want to create the opposite affect mixing grey with neutral tones such as beige or white. If doubt the blue is the color more game gives joined grey, because according to the chosen key the room will be more or less relaxing or lively, but always based on the harmony of the mixture.
Dare to try at home, is a background color that looks good anywhere and not get tired, and it will highlight the other decorative elements.