I have been knitting very diligently on the Child's Placket-Neck Sweater from Last-Minute Knitted Gifts. I get to the neck placket, follow directions, knit for 8 more rows, and realize that the placket is crazily off-center. I KNOW I counted right, because it didn't seem on center the first time, so I counted twice.
I check for errata, and of course, there it is. Instead of ending 18 st before the marker indicating the start of a new round, I am supposed to end 24 st. Duh! (insert eyeroll here). I had to rip back eight rows, and now knit them again. Grrrr.