Color is crucial to design.
The absence of it is as well, but maybe we'll get into that later. It is what makes something recognizable and pleasing to the eye. In the world of art, it documents history; eg. bright, bold colors may represent the 50s Pop Art movement. However, business takes art–I mean graphic design, to a whole other science. Quality design is make or break for businesses these days. This is because most businesses rely on their online presence...and who wants to spend their time on a busy site or trust someone with a sketchy logo? Not me!
Color is symbolism. Blue symbolizes a bright sky for some and sadness for others. Ah! Good question––what kind of blue? Well, that's where a graphic designer comes in. They're going to know what color tells the story, what shade sets the mood... On a landing page, maybe you want your social media links to be highlighted. A graphic designer will pick brand-appropriate colors to bring the links to a consumer's attention.
I have always been interested in the symbolism of color. Purple representing royalty and riches, red representing anger or power, yellow–happiness, green–envy... Being able to push those boundaries and challenge the viewer's perspective. As we know, not everyone's life is the same, and thus their view on certain colors might not match the symbols I know. An example of pushing the boundaries with color, is this monochrome painting I found on Pinterest: