A specific example of warning is Horatio's attempt to stop Hamlet from following the Ghost. In Act I, scene 4, Hamlet is on the platform with the other men when the Ghost appears yet again. It is his first time seeing it, & Horatio tries to stop him from going with the spectre. After all, none of them know what it truly is, and they have no way of knowing whether it intends to harm them or help them. Horatio relates these fears to Hamlet:
What if it tempt you toward the flood, my lord,
Or to the dreadful summit of the cliff
That beetles o'er his base into the sea,
And there assume some other horrible form,
Which might deprive your sovereignty of reason
And draw you into madness? Think of it.
The very place puts toys of desperation,
Without more motive, into every brain
That looks so many fathoms to the sea
And hears it roar beneath.
Thus Horatio essentially begs Hamlet to think before he acts. He offers a warning against the possibly malevolent spirit, but Hamlet is determined to hear what it has to say. One can argue whether that was the best choice of Hamlet's life.
A specific example of madness would be Ophelia's last moments on stage. She sings several songs, all connected with the loss of virginity. She is clearly distraught over the death of Polonius (some productions have her enter wearing her father's clothes). She gives flowers to everyone, each symbolizing a different emotion, command, or action. she has become the extreme for women living in an oppressive, male-dominated society, and her madness is a result of those around her consistently trying to manipulate and use her.Her last words are those of hope however.
I hope all will be well. We must be patient. But I can- not choose but weep, to think they would lay him i' the cold ground. My brother shall know of it. And so I thank you for your good counsel. Come, my coach! Good night, ladies. Good night, sweet ladies. Good night, good night.
She speaks coherently of her father's grave, but offers a final farewell to all.
Finally, a specific example of death is Polonius' accidental murder at the hands of Hamlet. Some may say Polonius was asking for it, that his web of lies and spying would come crashing down around him at some point. Others argue that Hamlet is rash and frustrated at his inability to kill Claudius, so he lashes out at whomever is handy. In this case, it's Polonius. Hamlet kills him in Gertrude's chambers, seeming to hope it was Claudius. Afterward, Gertrude is almost in shock at her son's action, but Hamlet feels no remorse.
Thou wretched, rash, intruding fool, farewell!
I took thee for thy better. Take thy fortune.
Thou find'st to be too busy is some danger.
So he tells Polonius that he should have considered the danger before he went digging where he didn't belong.