What's missing in this picture?

That's right! one of the needles! Instead of grabbing the free one to knit with, I simply grabbed and puled out one that was in use. Well, well no harm done and this gave me a reason to take a picture of my ongoing sock and show it to you.

I'm knitting much tighter when I use two yarns which leads to that the ribbing on top (or in the bottom of the picture) is wider then the rest of the sock. I assume that it shouldn't be like that. Has anyone got any tip? Do I have to frog, or could I just leave it like this?