Color can make or break any artistic project. It doesn't matter if you're painting your house, knitting a scarf, or beading a bracelet-- color is the first thing most people notice, and if the colors you choose "work" for the project, the effect is profoundly positive. If, however, you choose colors that don't "work"-- either they don't work together, or they don't match the project-- they can get in the way of the artistic statement you are trying to make.
I'm not trying to say that every color needs to harmonize perfectly-- trust me, I'm all about using bright and unexpected color combinations-- but I think it's important to understand the way that color works (and, more importantly, the way colors work together) if you want to make the most out of crafting.