There is not a thing wrong about working with what you are comfortable with. It takes some people years to figure out what they like! :-)
Adding white or very light into a block can make the other colors sparkle and help the eye move across the quilt top easier. I once saw a Basket pattern with HST border all done in muted red and brown (sashing, too) but each basket had white as the background color for that block. It added excitement to an otherwise dull quilt top. Just think of white or light colors as the mat in a picture frame, used to highlight the main object and not to BE the main focus.