Sir Gawain and the Green Knight?

The perception and reality part could be the way the characters are portrayed. Sir Gawain was a knight, and they were supposed to be morally superior human beings, close to perfection, the reality is that he lied to the green knight about the scarf that the green knight's wife gave to him in the final test. So the perception of the 'perfect knight' was shattered to reveal that they are, in reality, just like other people.