So, there's this guy, you know? the.effing.librarian. Irreverent, humorous, librarianish, all that stuff. He's also written a really interesting post on the history of "The Quiet Librarian," where he started out looking for the earliest published reference he could find on the shushing thing, and found a whole treasure-trove of information about the early days of librarianship and the never-ending battle with image. In answer to the questions posed at the end of the post, I agree, it's like a pendulum... but my favorite line is the last one:
"Maybe it keeps us interesting. It keeps everyone guessing about us. If so, that's kinda cool."