It is wonderful that nobody has ever yet fancied it to be sinful to scratch where it itches, and that it has never been determined that the only natural way of scratching is with such or such a finger and that it is unnatural to scratch with any other.
from Jeremy Bentham's "Offences Against One's Self" (find it here)
Not a library related quote, but what do you want? A one-trick pony? I know at least two. Nay.