Like a few others it drives me crazy when I have my quilt blocks all laid out on the design wall and still somehow sew the wrong sides of the blocks together and then don't notice until something is off somewhere else in the row or the next row. Like this purse I'm working on right now for my daughter. I'm using batiks and several prints are scattered around randomly for variety. Got one sewed wrong (too much talking when sewing with friends I'm sure) and then I had to reorganize several others after they were all laid out perfect. One little mistake can throw the whole thing off. So it's me that I find frustrates me.