My biggest frustration as a teacher, was one student constantly making the same mistake even though, one on one with samples, we went over the problem after her first attempt. Was I talking a foreign language? Were my written and verbal instructions not clear enough? I felt she had wasted her money because her attempts could not be used and I also felt like she had wasted my time because she could not--or would not--follow the instructions. (BTW the instructions were VERY simple--finger press the seam and trim leaving a generous 1/2 inch length of fabric. This was for tumbling string blocks that would be trimmed to a specific size later.)