Sometimes a quilt requires color as the background. I also like white on white or cream on cream as it seems to soften the starkness of a solid white or cream. Love blenders, too. All of these provide texture to the eye. If a quilt is for a bed that the back will be seen when turned back, I like to put a print there. Wall hangings can utilize muslin, broadcloth (did anyone gasp?) or a solid of some color. Wall hanging backs are for function, not beauty--my opinion.