As with anything to do with gauge this post comes with a huge caveat. Everyone knits differently and you might not have the same experience as me. That being said I find that often when I knit a plain vanilla stocking stitch sock I find that my usual 64st on 2.5mm needles doesn't work for me and the sock ends up being ever so slightly loose on the foot.
Instead I find that dropping to 60st for me (and from 72 to 68 for DH) gives a much better fit in plain stocking stitch.
Socks with a pattern or cable often have a slight degree of extra rigidity, unless there is a lot of ribbing. Plain stocking stitch however tends to have equal stretch in both directions. This makes for a beautifully smooth fabric - all the better to show off that gorgeous self stripe yarn - but which also has the potential to be ever so slightly baggy.
Going down just those few stitches creates the negative ease that is so crucial for a good sock fit.
Do you find the same thing ? I've love to know if you have the same experience too.