Having looked at a variety of critical studies, and having weighed the evidence, what do you consider to be the most important motives behind Iago's actions in Shakespeare's 'Othello'?

One of the most interesting and complex characters in 'Othello' is "Honest" Iago. His manipulative language, deceptive nature and the ambiguity surrounding his motives and actions engage the audience from the beginning. Although the importance of Othello's tragic flaw is undeniable, Iago's coolly manipulative nature plays a definitive part in Othello's downfall. He predicts and largely controls other characters' actions and is the driving force behind the play's action. Iago manipulates Othello's insecurity provoked by …

…is deceiving himself with excuses, and the audience with him. This perhaps indicates what he meant by "I am not what I am". Also, Iago makes very few references to his 'motives' after Act One, indicating that he is enthralled in his evil, and has lost the need to justify his immoral actions. Thus, it is difficult, to determine which of Iago's motives, if taken to be true, are the most important. S. Hattersley (March 2002)