You need to always pull up your bobbin thread because once in a while if you don't, it will make a really nasty knot on the back of your quilt. I just did a few tiny stitches before quilting in the ditch. I am NOT sure if this has been passed down to new people who are machine quilting, but it is BEST to have a busy print on the back so that any error in your quilting will not be noticeable. I was taught that over 25 years ago.