I was in the judging of quilts for our guild's quilt show, and I heard that comment from the judge many, many times. In general she was talking about how straight the seams are....especially on long straight seams. She was being very critical of those..."Straight seams need to be straight". So, wherever you have long seams, be sure you maintain your 1/4", and be sure you sew straight! That's what it means.