I never thought I had a problem with gauge. I always knit to gauge; I mean, I know knitting experts laugh at people who say that and it comes back to bite them in the butt, but seriously, I've never had a problem. Until now... (see above for the sad truth. Lefty sock is 2.75" whilst its righty brother is a full 3". That's a good .5" around! Zoiks!)
The difference between sock #1 and sock #2 was so dramatic, I thought I had put the wrong number of stitches on the needles! I had apparently done the gaps between needles on sock #2 extra tight, and forgotten to release that tightness on the stitches in the interim. Stheriousthly, deewwwd, I needed to mellow out. I frogged the second sock and tried again in a less uptight frame of mind, and it came out a little more like the first. It is a smidge longer than the 1st, which happened with the last pair also, but that's what I get for eyeballing it, I err on the side of adding a little too much.