Iago. Think, my lord!

Othello. Think, my lord! Alas, thou echo'st me,
As if there was some monster in thy thought
Too hideous to be shown.

The stops and breaks, the deep workings of treachery under the mask
of love and honesty, the anxious watchfulness, the cool earnestness,
and if we may so say, the PASSION of hypocrisy marked in every line,
receive their last finishing in that inconceivable burst of
pretended indignation at Othello's doubts of his sincerity.

O grace! O Heaven forgive me!
Are you a man? Have you a soul or sense?
God be wi' you; take mine office. O wretched fool,
That lov'st to make thine honesty a vice!
Oh monstrous world! take note, take note, O world!
To be direct and honest, is not safe.
I thank you for this profit, and from hence
I'll love no friend, since love breeds such offence.

If Iago is detestable enough when he has business on his hands and
all his engines at work, he is still worse when he has nothing to
do, and we only see into the hollowness of his heart. His
indifference when Othello falls into a swoon, is perfectly
diabolical.

Iago. How is it. General? Have you not hurt your head?

Othello. Dost thou mock me?