Culture shock to me, as someone who has visited 20-ish countries and lived in 2, is more that "things are almost normal and like what you're used to, but just not enough to be comfortable", and as a result you end up perpetually on edge and perpetually adjusting just outside your comfort zone. It's jarring and difficult, a little like the room in Orwell's 1984 where the corners aren't quite straight, and things are
just out of focus.
I didn't get culture shock in Tokyo, because it's just so different to everywhere else I'd been that I completely stopped the usual comparisons and just gave up.