"Why did you even go to vet school if you later decided to become a librarian?"
"Why would you take antropological and etnological classes if you're already a librarian?"
"Why do you like reading romance novels? You should read quality literature."
Why this? Why that? Why, why? Why take an interest in something that is not 'your' profession?
I mean why not? Why should anyone tell you that you shouldn't read or study something that you like?
Yesterday a kid and I had a debate about what would happen if cows took over the world. (They would have hard time eating humans since they only have teeth on their bottom yaw). After that he said "you know, it's nice to have a librarian that knows stuf" and that was one of the best compliments I've ever gotten.
So go ahead read what you like, study whatever interests you and have long debates with kids about the topics you never dreamt of!
When are you (a little bit) too obsessed with a book?
It's when you figure out that the last book in a series is not coming out in your language this or the next year! So you spend a few hours searching for a hacked version in french on the internet. Finaly you find it and than copy it part by part in Google Translate so you can read it in english...