I can't do a random scrappy quilt either! What I do is controlled scrappy, where I select some scrap yardage, buy the rest if I don't have enough for that pattern/size and combine these for a quilt. Usually I am grouping based on colors first, then print/value.
I have fabrics that just never seem to "fit", and I just donate those to others making charity quilts who need fabric. It just isn't worth it to try to force ourselves to make something we don't like!!!