Come, go with me: I will go seek the king.
This is the very ecstasy of love,
Whose violent property fordoes itself
And leads the will to desperate undertakings
As oft as any passion under heaven
That does afflict our natures.

Near the end of Act II, scene 1, Ophelia is having a conversation with her father, Polonius. She describes the meeting that she has just had with Hamlet. The Prince of Denmark, according to Ophelia, came to her disheveled and pale. He merely looked at her, sighed deeply, and withdrew from her presence. Ophelia is puzzled and alarmed at Hamlet's conduct, but Polonius assures her that Hamlet's erratic actions are surely a result of love. His explanation to his daughter is beautifully worded, using the phrase, "As oft as any passion under heaven/That does afflict our natures." Furthermore, Polonius entreats Ophelia to go with him to see the king (to talk to his majesty about Hamlet.) Polonius goes on to say that Hamlet's "ecstasy" is a result of his passion for Ophelia, or that he is "crazy in love." Sometimes, Polonius says, love causes the will to take leave of its senses and cause its master to act in ways that seem unnatural; Polonius adds that other emotions that humans possess can have uncharacteristic effects on people. At this point in the play, Hamlet has only just revealed his plan to act insane, in order to watch the newly-crowned king, Claudius, closely. The reader, unlike the majority of the characters in Hamlet, knows of Hamlet's plan of action: keeping a close watch on his stepfather under the umbrella of "madness;" this changes Hamlet's actions toward Ophelia from those dictated by an addled mind to those of calculated manipulation. Hamlet is 'proving' his "insanity," one royal courtier at a time. I felt that this passage was important not only because of the expressiveness of speech that Polonius utilizes, but also because by Ophelia and her father's contemplation of Hamlet's madness we see that the Danish prince's ruse is indeed working; in the court's mind, Hamlet is losing his senses.