Color theory is a central and often overlooked area of design. On a simple level, the colors on the warm side of the spectrum- such as red and yellow- are bold, uplifting and energetic. The color spectrum's cooler counterparters -blue and green- exude calmness and feel more reserved. Color theory is particularly relevant when it comes to branding: on an emotional level, in terms of how consumers feel when they look at it; but also on a practical level, in terms of market standout.
For a company to effectively 'own' a color in its sector can provide an enormous competitive advantage, achieving instant recognition- in some cases, even without a logo, or even a mention of its name. That's the power of color, done right.