Bookcase = Adult???

This was on an episode of a show that used to be on TV. Well, I guess it still is but it's in reruns now. Anyway, the woman on there broke up with her boyfriend because he had an empty bookcase in his apartment and didn't care to fill it up. According to her, if you're an adult your bookcase should be filled. This got me to thinking because I have 3 bookcases and 2 other shelves stuffed to capacity with books. Does this make me any more or less of an adult? Additionally, does the contents of the shelves matter? I have tons of books but I would say that maybe a quarter of them would actually be considered literature and not just leisure reading. So does the fact that my bookshelves contain Harry Potter and Nora Roberts' books make me immature?

Can you accurately judge a person by the cover of their books?