Adobe Illustrator Color Wheel

Adobe Illustrator Color Wheel

The Reason why businesses have to use certain colors is because certain colors represent different emotions. If they use the wrong Color/emotion people might get the wrong idea with their product, and thats bad.
Red- associated with energy, war, danger, strength, power, determination as well as passion, desire, and love.
Green-symbolizes growth, harmony, freshness, and fertility.
Blue-symbolizes trust, loyalty, wisdom, confidence, intelligence, faith, truth, and heaven.
Black-associated with power, elegance, formality, death, evil, and mystery.
White-associated with light, goodness, innocence, and purity.
Purple-symbolizes power, nobility, luxury, and ambition.
Yellow-associated with joy, happiness, intellect, and energy.
Orange-represents enthusiasm, fascination, happiness, creativity, determination, attraction, success, encouragement, and stimulation.
Brown-represents reliable, genuineness, sad, wistful.
http://www.infoplease.com/spot/colors1.html
http://www.color-wheel-pro.com/color-meaning.html