Mistakes? Do you mean like cutting fabric and after it's all cut, discovering there isn't enough? Or maybe using the fabric set aside for binding, for something else? Or do you mean stuff like sewing the right side of one block, to the wrong side of another . . . and ripping it out, only to sew it wrong again? Or are you referring to stuff like looking away, for just a SECOND, while sewing? I'd rather not answer the question . . . .