I wont say, I've had a complete quilt go wrong. What is a disappointment is when cutting all of the pieces for a quilt out. And either the triangles, are too small, or the sq's are too small, or something. Or the measurements are wrong, or directions. I'm working on some blocks for my long arm lady friend. I cut out sq's-3 5/8''..192 to be exact. I had to recut them to 3 3/4". And I even used the templates in back of the book.