It depends on how big the pieces and patterns in the fabric are, if is small pieces then the colors/patterns will blend and no one piece will be discerable. The smaller the more they just visually blend together. Its also the general guigleine I have for what I call "ugly" fabrics .. just cut them small and no fabric is ugly.

I just use what i like

I have a tendency to buy "seasonal" fabrics not "holiday"ones. By being more general in my fabric purchases, I have the freedom to select fabrics based on the colors I wish to use and not be concerned about the print.

For true scrappy quilts, I use whatever is in my scrap basket. For controlled scrappy quilts, I select from my stash based on color.

Ditto.. I use whatever I have scrappy..