Final answer:
Iago’s reason for hating Othello in Shakespeare’s play is multifaceted, but if a single reason must be identified, it is a combination of jealousy and revenge.
Step-by-step explanation:
The character of Iago in William Shakespeare’s play Othello is driven by multiple motives for his hatred of Othello. Iago's resentment emerges from various sources, including professional disappointment and racial disdain. However, one of Iago's primary reasons for hating Othello is jealousy. This jealousy is multi-faceted: it includes jealousy over Othello's promotion of Cassio over Iago, as well as Iago's unfounded suspicion that Othello has been involved with his own wife, Emilia. Additionally, Iago seeks revenge against Othello for these perceived slights and betrayals.
Thus, while Iago’s motivations are complex and layered, if we have to identify a single motivating reason, it could be framed as a combination of jealousy and revenge. Yet, in different interpretations of the play, any of these factors - jealousy, revenge, betrayal, or misunderstanding - could be viewed as the single biggest motivating factor in isolation.