This is what happens when you take the directions in a pattern as suggestions, not instructions. Beavering away on my Gradient Yoke Sweater, I get down near the hemline where it says to put a life line in the row to which the edge of the hem will be sewn after its turned. Pffft. As if I couldn't follow a row of purl bumps on the back side of stockinette. I tootle on down, purl a row for the bottom of the hem fold, and knit on 8 more rows, ready to hem. [Boring technique note: often a knit hem is made by running a circular needle through the appropriate row and binding it and the edge row off together. This pattern said sew, so I was going to sew.] Came time to sew the hem and--uh oh--I wasn't as good at following those purl bumps as I thought. The result was all skew-whiff and uneven and looked terrible. So terrible I didn't even take a photo of how terrible.
I could either abandon the sweater at this stage to the Heap of Malfunctioning Rubble, or pull my socks up, undo what I had done, and put my life line in after the fact. Reader, I put in the life line. And it made all the difference, see?