Color is a big deal to people. Scientists say we are one of the few creatures that sees color and it was critical to our ancestors' survival.
Color works great in marketing.
There are lots of theories and opinions about what works best. Many say Blue lends a feeling of quality and trust. Yellow tends to get attention better than any other color, but is hard on the eyes. Designers use Yellow to spice up a headline or product name, but put the rest of the ad or package in warmer colors. One study showed that the color combination with the most powerful psychological effect was yellow title, white text, on a dark blue background.