Final answer:
In Act IV of 'A Midsummer Night's Dream,' Puck exclaims, 'Lord, what fools these mortals be!' highlighting the foolishness of humans.
Step-by-step explanation:
In Act IV of A Midsummer Night's Dream, Puck exclaims: "Lord, what fools these mortals be!" This line is a commentary on the irrationality and foolishness that Puck observes in the human characters' behavior throughout the play. It is not to be confused with other famous lines from Shakespearean works such as Hamlet or Romeo and Juliet.