First, I should mention that I'm very old. As in I was taught that $1$ is a prime number. So I get annoyed when things change, even if it's for the better.
So now (October 9, 2017, if I recall correctly) they've redesigned math.SE so that it's more consistent with other StackExchange sites.
And now I have no idea how to log out.
This wouldn't be a big deal if I was logging in from my home computer (that one doesn't connect to the Internet, long story). Here at the university library they take that thing that kind of seriously.
Normally I look at "Questions that may already have your answer" but today those have been singularly unhelpful.