Act 1, Scene 4, Duncan: 'Oh worthiest cousin! The sin of my ingratitude even now was heavy on me'
He apologises to Macbeth for not promoting him earlier.
The use of exclamation mark displaying his heightened emotion.
Good kingship shown as he is willing to reward people who are good, but this is his fatal flaw because he cannot distinguish between good and bad.
Dramatic irony as the audience is aware of Macbeth's evil side.