I prithee, speak to me as to thy thinkings,
As thou dost ruminate, and give thy worst of thoughts
The worst of words.
– William Shakespeare
Othello, Act 3, Scene 3. When Iago plants suspicions into Othello’s head about the relationship between Cassio and Desdemona, Othello begs him to speak his worst thoughts. This shows the effectiveness of Iago’s manipulations, with Othello now beginning to entertain the possibility of his wife cheating on him.