Conflict is often created due to a lack of communication and Othello is no different. Iago, in fact, thrives on miscommunication, inferred meaning (entendres) and double meanings.
Iago is the first to show his displeasure after he has been passed over for promotion. When Roderigo suggests that Iago should "not follow him," Iago is quick to note that there will be consequences to Othello's decision:
I follow him to serve my turn upon him. I.i.42
Iago goes on to basically warn Roderigo because Iago himself admits
“I am not what I am,” I.i.66
Iago knows how Roderigo wanted to court Desdemona and will manipulate him to create conflict and mistrust between Brabantio and Desdemona. As Iago says to Roderigo:
Let us be conjunctive in our revenge against him.."I.iii.365
Brabantio is immediately enraged by Roderigo when he is roused from sleep and Iago's use of coarse language - "you'll have your daughter cover'd with a Barbary horse"I.i.113- creates enough conflict to incense Brabantio against Othello,at this point.
The play itself is set up in Act I.i. and the conflict that can be expected is all but announced:
all the action stems from Iago manipulating other characters and wreaking havoc in their lives so that his own life may be what he feels is owed to him
Iago's schemes to subvert Othello's happiness by upsetting Desdemona's father are in vain and later, Iago sets Cassio up to get involved in a bar brawl. This serves a double purpose as Iago is able to discredit both Cassio and Othello; Othello obviously making a poor decision choosing Cassio.
“Cassio I love thee; / But never more be officer of mine.” II.iii.241
Cassio plays right into Iago's hands, as Iago counsels him to plead with Desdemona - thereby adding circumstantial evidence in Iago's plot to destroy Othello.
"I'll pour this pestilence into his ear.I.iii.345
The play intensifies and the relationship between Othello and Desdemona all but disintegrates as Othello demeans Desdemona and himself:
“I took you for that cunning whore of Venice / That married with Othello.” IV.ii.90
Iago is now so motivated as his plan comes together and he is still manipulating Roderigo who will attempt to kill Cassio. Even in Act V Othello still refers to "honest, honest Iago."V.ii.157.
When Othello is persuaded by Emilia,both realising they were duped over the handkerchief and that Iago is a liar and a fraud and Desdemona was pure, Othello wants to kill Iago. He is prevented from doing so and ultimately kills himself:
I kiss'd thee ere I kill'd thee.....killing myself...."V.ii.361
an ultimate resolution of the conflict.