Making a virtue out of necessity is extremely satisfying. While you were describing the solution to your mistake, I kept thinking: "But what about the side seam? It's also the wrong way round." The fact that you ultimately solved it with a French seam and thus killed two birds with one stone makes your end result a beautifully rounded affair. Very well done. There's nothing more annoying than having to undo seams that have just been closed, I totally agree. The creative mind sees it as a challenge, the lazy one a nuisance. HaHa! I admire any activity that expands and refines one's craft skills.