In A Preface to Paradise Lost, C. S. Lewis discusses Book IX, lines 811 ff., of Paradise Lost, in which Eve has just eaten the fruit, and is now planning to give it to Adam. She reasons that if she is going to die, she must have Adam die with her. As Lewis points out, Eve is planning to actually murder Adam, but the reader may not even notice this, because the shift in her thinking is so subtle. Lewis then makes an insightful comment about human nature:

If the precise movement of Eve's mind at this point is not always noticed, that is because Milton's truth to nature is here almost too great, and the reader is involved in the same illusion as Eve herself. The whole thing is so quick, each new element of folly, malice, and corruption enters so unobtrusively, so naturally, that it is hard to realize we have been watching the genesis of murder. We expect something more like Lady Macbeth's 'unsex me here'. But Lady Macbeth speaks thus after the intention of murder has already been fully formed in her mind. Milton is going closer to the actual moment of decision. Thus, and not otherwise, does the mind turn to embrace evil. No man, perhaps, ever at first described to himself the act he was about to do as Murder, or Adultery, or Fraud, or Treachery, or Perversion; and when he hears it so described by other men he is (in a way) sincerely shocked and surprised. Those others 'don't understand'. If they knew what it had really been like for him, they would not use those crude 'stock' names. With a wink or a titter, or in a cloud of muddy emotion, the thing has slipped into his will as something not very extraordinary, something of which, rightly understood and in all his highly peculiar circumstances, he may even feel proud. If you or I, reader, ever commit a great crime, be sure we shall feel very much more like Eve than Iago.