No matter how much we know about the other person, there is always something going on in that other heart and that other head that we don't know but can only ponder. And no matter how we explain ourselves to someone else, no matter how open we are, there is always still something inexplicable, something hidden and unknown in us, too.
Michael Shurtleff (2009). “Audition: Everything an Actor Needs to Know to Get the Part”, p.95, Bloomsbury Publishing USA
