Another thing I have noticed while piecing blocks is that if one of the fabrics is lesser quality than the other one, while sewing, even though the ends match prior to, your machine foot is pushing the top fabric toward you and your pieces will not end up even at the end. Always being off a smidge. This will make matching seams up even more difficult. This just shows me that not all fabric is created equal. I already knew that but it proved it even more to me. I had never noticed it before.