The theory states that neutral colours are neither cold nor warm. But last time this term is used to speak about particular colours - black, gray, beige and brown. Neutral colours are considered to be exquisite, because in their use the main accent us made to design, cut or architecture. Neutral colours don't distract attention. People pay attention to texture and content.
Great amount of neutral colours are good for use in spacious rooms. They are good by themselves and in combination with other colours. They perfectly suit for background, as they intensify main colour - that's why black is often used with red. Another example is Indian jewelry of silver and turquoise (gray and blue).
White colour, i.e. complete absence of pigment, is usually associated with purity, chastity, novelty, peace and innocence, and with high quality too.
Though white, formally, is complete absence of pigment, it has a great variety of hues. If we paint one surface blue-white and the other yellow white, the difference will be obvious. The first hue reminds mountain glaciers, the second reminds sea pearls. However, every hue of white is associated with simplicity. White colour is a classic choice for all times.
However, white colour may arouse negative associations - white lie, white elephant, and white flag of defeat. Overuse white colour and you'll get the feeling of sterility and hospital atmosphere. If you use white without any accents or adornments, your costume may seem cheap and primitive like white plastic cups and plates. If you painted your bathroom cold blue-white you will hardly get warm even under hot shower. White also possess a very useful property of visual space extension.
Gray is a classic neutral colour. It reflects all the colours and non of them dominates in it. It is a perfect colour for background. It is moderately conservative, traditional and speaks about intelligence.
To smooth over the neutrality of gray you can make it "warm" by adding a bit red or yellow, or "cool" it by adding green or blue.
In nature warm gray is found in granite, cold gray - in slates. Modern technology achievements allow getting gray with pink or lavender hues, and hundreds of other interesting colours. Silver, metallic gray, speaks about wealth. Dark gray is an indispensable attribute of a serious businessman.
Does gray send any negative signals? Very few.
Gray colour may seem old, dull and uninteresting. But in combination with other neutral or bright colours gray looks strong, energetic, exquisite and beautiful.