What metaphors are used in The Reader by Bernhard Schlink?

One vacation morning Michael leaves a note for Hanna telling her he has gone out for breakfast and will return shortly. Hanna wakens and finds the note but being illiterate, cannot read it and fears it is some sort of goodbye note. She destroys the note and, when Michael returns, slashes him across the face with a leather belt in a rage. Michael apologizes and accepts her blame and then tries, unsuccessfully, to find the note. The missed communication is reminiscent of many other similar circumstances in literature and also serves as a metaphor of how incapable Hanna is of truly communicating with Michael.