Librarian here.
I go through phases of loving it, and thinking, my job is great, and times wanting out and into something new. I'm freelance in my other career though and libraries work well with that (amazing how many musicians, artists, writers, makers come to work in libraries.)
It's lovely to be exposed to books, ideas, people who like books, etc. Colleagues are also really nice. Occasionally we have challenging situations though, there is a lot of shelving, and it can feel kind of repetitive.
I'm in a group of libraries, so in theory you could apply for a job in one and be placed in another branch. This happened to me, and I minded badly at the time, but now love the branch I am in (most of the time.)
There is a lot of social energy needed though, so sometimes you can feel kind of drained on the chatting to people front, and not be up for socialising, if that makes any sense.
We are about so much more than books.
Library cuts are a huge issue though, and lead to many complaints. PM me if you'd like to know more as it's run by city council, so can't go into details about where, etc.