Honest to God it's the scant 1/4 seam. I sewed clothes for over 40 years before I ever learned to piece a quilt. I believe with sewing, it's a 5/8 seam so it was much larger than a 'scant' 1/4 as my teacher said over and over. I was so embarrassed I couldn't sew it. And this went on for over 2 years. The other problem I had was cutting accurately with the rotary blade, when I folded my fabric, I made the V in the strip. I could cut anything but those long strips. I am far from perfect today, but I do sew a neat 1/4 seam and no more V's in my strips finally.