I was having trouble sewing a difficult spot once and made the mistake of asking my husband. He said, "Don't you have to sew faster to make it work?" Like the stitching speed matters at all to the stitch, and like I wanted to sew something *wrong* really fast...
And for embroidery -- I love redwork. I did something recently for my niece, and my sister said, "It looks a little plain -- can't you fill it in with color?" I just looked at her. And I laughed on the inside!