I have that within which passeth show,
These but the trappings and the suits of woe.
(I.ii.)

When Hamlet’s mother asks him why he still seems so upset about his father’s death, he replies that he doesn’t just “seem” to be in mourning, he has feelings within himself that surpass what other people can see from the outside. This quote resonates with many other parts of the play that suggest Hamlet has an unusually rich inner life—that he has more going on inside him than outsiders can see or understand. At the same time, the distinction Hamlet draws between how he seems and how he really is also resonates with the theme of deception that runs throughout the play: both Hamlet and Claudius go to great lengths to hide the truth about their actions and intentions, but so do most of the other characters.

O God, God,
How weary, stale, flat and unprofitable
Seem to me all the uses of this world!
(I.ii.)

Hamlet’s first soliloquy shows us that his feelings run much deeper than the people around him realize. Not only is he grieving for his father and angry with his mother for remarrying, he is sick of life itself. This quote is the play’s first hint that Hamlet might be suicidal, and the lines make clear that Hamlet is extremely troubled even before he hears the Ghost’s story.

What’s Hecuba to him, or he to her,
That he should weep for her?
(II.ii.)

Hamlet has just watched a player from a visiting acting troupe perform a speech describing the slaughter of King Priam and the subsequent grief of his widow, Queen Hecuba, at the end of the Trojan War. Hamlet expresses amazement that the Player can shed real tears out of sympathy for Hecuba, a figure from ancient history, and he contrasts the Player’s emotiveness with his own inaction when confronted with this father’s murder. Throughout the play, Hamlet wrestles with the idea that performances can seem more real than “reality.”

The play’s the thing
Wherein I’ll catch the conscience of the King
(II.ii.)

Hamlet cannot decide whether his uncle is guilty of killing his father, so he decides to gather more evidence before he acts. Hamlet’s plan is to stage a play about a similar murder and watch his uncle’s reaction to the action onstage. But Hamlet has already repeatedly expressed his doubts that external appearances can be trusted, so we have reason to think that Hamlet may be deceiving himself in thinking that this stratagem will solve his problem.

To be or not to be—that is the question
(III.i.)

In this line—the most famous line in all of Shakespeare—Hamlet asks whether it is better to exist or not to exist, or to put it another way, whether he should commit suicide or continue living. Hamlet’s central struggle is with his own uncertainty. In soliloquies like this, we see that his uncertainty extends way beyond practical matters such as whether he should believe the ghost about his uncle’s guilt, to philosophical questions about the value of life and death. In the end Hamlet decides it’s better to live, but only because he can’t be certain what happens after death.

I have heard of your paintings well enough. God hath given you one face and you make yourselves another […] It hath made me mad.
(III.i.)

Hamlet here claims that the deceitfulness of women, who wear makeup to look like something they’re not, is what has driven him mad. Hamlet’s madness is one of the more ambiguous elements of the play. While at certain times he explicitly says he is only pretending to be mad, at other times he seems possibly sincere about admitting he’s lost his grip on sanity. Throughout the play, Hamlet does seem genuinely troubled by his feelings about women, heaping abuse on both Gertrude and Ophelia with no particular purpose.

Do you think I meant country matters?
(III.ii.)

When the court assembles to watch Hamlet’s play, Hamlet is supposed to be watching King Claudius for signs of guilt. Instead, he seems preoccupied with his misogynistic feelings about women. When Ophelia tries to ask him polite questions about the play, he responds with cruel sexual jokes. In this line, the word “count-ry” is a pun.

Your worm is your only emperor for diet. We fat all creatures else to feed us, and we fat ourselves for maggots.
(IV.iii.)

Hamlet says this to Claudius, having been escorted into Claudius’s presence by armed guards after killing Polonius. At this point in the play Hamlet has to convince Claudius that he’s insane he won’t be held accountable for the murder or be perceived as a direct and immediate threat to Claudius, and it works—Claudius does think he’s dangerous, but also that he’s out of his mind. Hamlet’s words literally mean “The worm has the most exclusive diet (because it eats humans after they’re buried). Humans fatten other animals to eat, but they also fatten themselves to be eaten by worms.” The words can be taken as evidence of Hamlet’s morbid obsession with death and decay, or as a reminder that we are all mortal, but they have a menacing undertone as well, subtly reminding Claudius that he is mortal and will at some point be food for worms.

There’s a divinity that shapes our ends,
Rough-hew them how we will.
(V.ii.)

Hamlet makes this remark to Horatio while explaining how he woke up on board the ship to England and on a sudden impulse snuck in and stole the king’s letter from Rosencrantz and Guildenstern. The point Hamlet is making is that sometimes when we act impulsively or rashly things turn out well, showing that there is a divine power shaping our lives. The significance of Hamlet’s remark is that it shows how much he has changed since the first half of the play. In the early acts, Hamlet had been indecisive but also very preoccupied with knowing the truth and determining the best thing to do. After he kills Polonius, and through the end of the play, Hamlet acts much more recklessly and is prepared to do things and let the chips fall where they may. This attitude carries him into the last act, where Claudius and Laertes have laid a trap for him in the fencing match, but Hamlet is no longer particularly concerned with what happens to himself and gladly accepts, hoping the outcome will somehow fall in his favor.