Macduff's refusal to attend Macbeth's coronation is the first sign of his disrespect for Macbeth. He is sure that Macbeth murdered King Duncan and that he has no right to the crown. Macduff will be one of the first to flee to England to lend his support to Malcolm, Duncan's eldest son, who is raising an army to overthrow Macbeth. Macbeth naturally resents Macduff's conspicuous absence at the coronation and understands that the Thane of Fife is a powerful enemy who could influence others to turn against him as well. Then when he learns that Macduff has fled to England, he decides to take revenge and make an example of him by murdering his entire family. Macduff might have been wiser to attend the coronation and to conceal his suspicions and hatred, which is what Banquo did, although Banquo was just as outraged and disaffected as Macduff.