Taint not thy mind
In Act I, Scene V of "Hamlet," the ghost of Prince Hamlet's father informs him that Claudius, Hamlet's uncle and his father's brother, murdered Hamlet's father to steal his crown and his queen. This crime is described in a string of condemnations to place the audience in no doubt as to the uniquely heinous nature of the murder: "Murder most foul, as in its best it is, But this most foul, strange, and unnatural."
Following hard upon come battalions of modifiers to describe just how many cultural taboos the murderer is guilty of breaking. The killer is described as a "serpent," "incestuous" (for taking his brother's wife), "adulterous" (for same), guilty of "witchcraft," "traitorous," and, well, I could go on, but you get the idea. Even Claudius himself thinks so, as Hamlet overhears him praying for forgiveness for being guilty of "the primal eldest curse ... a brother's murder (see Cain v. Abel--Cain 1, Abel 0). If anyone deserves to get the book thrown at him, it is this guy. Go get 'im, Hamlet!
Hamlet's father wants Hamlet to avenge his death, but also gives his son a warning: "Taint not thy mind." That is, in his pursuit of justice against this person who is the poster child for what is rotten in Denmark, don't let it turn you, dear Hamlet, into a monster as well. Those who have read or seen "Hamlet" know how poorly Hamlet followed this advice. No fewer than eight more people die as a result of Hamlet's tainted mind. To paraphrase Nietzsche, hunting monsters can be a fast track to becoming one yourself. But Hamlet is only........
