The more we get to know someone, the more we find that we might not like. Sort of like Donkey in "Shrek" explaining about the layers of an onion. As you've read the bulk of the play, Oedipus's character clarifies, and some of the pieces aren't so wonderful. Consider his actions and choices, and determine his flaw. What is it, and what is the evidence that supports it? What mistake in judgment is caused by his flaw? What does the mistake ultimately lead to? Be clear about the flaw, the mistake in judgment, and the consequences.