I usually press my seams open and the LA quilter I sometime use never says there is a problem. She is a good friend and will tell me not to do something if it causes her a problem. She has said many times she prefers the seams to be pressed opened. I am guessing the seams are the problem, the stitch length is too long or the piecing thread is poor quality. I don't understand how someone can use a low quality thread to sew high quality fabric but I see it all the time in classes and at sew days.