Othello is the most famous literary work that focuses on the dangers of jealousy. The play is a study of how jealousy can be fueled by mere circumstantial evidence and can destroy lives. (In Othello, the hero succumbs to jealousy when Iago convinces him that Desdemona has been an unfaithful wife – in the end, Othello murders his wife and then kills himself.) It is interesting that Iago uses jealousy against Othello, yet jealousy is likely the source of Iago's hatred in the first place. In Othello, jealousy takes many forms, from sexual suspicion to professional competition, but it is, in all cases, destructive.
The reason Iago chooses to hurt Othello by making him jealous is that Iago is consumed by jealousy himself.
In Othello, Shakespeare proves that jealousy is inherently unreasonable, as it is founded on the psychological issues of the jealous person, not on the behavior of the one who prompts the jealous feelings.