It occurs to me that the only difference between a Shakespeare tragedy and a Shakespeare comedy is the final act. The plot of Othello is almost identical to the plot of Much Ado About Nothing. At the end of Much Ado About Nothing, Claudio discovers that Hero was faithful to him after all, so he marries her and everybody goes dancing. At the end of Othello, Othello does not discover that Desdemona was faithful to him, so he kills her and commits suicide. Switch the endings and Othello becomes a comedy, Much Ado a tragedy.