Question: why did iago hate othello?
Answer: Iago says in Act I, Scene 1 that he hates Othello because Othello has passed him over as a lieutenant. ... In other words, Iago believes that Cassio knows less about fighting than a spinster, or old unmarried woman, does. In addition, Iago suspects that his wife, Emilia, has cheated on him with Othello.