Hamlet appears for the first time in Shakespeare's Hamlet in act 1, scene 2. After he enters, he just stands there, probably a little off to the side, separated from lords and the attendants to King Claudius, his uncle, and Queen Gertrude, his mother.

Hamlet isn't paying attention to what's going on which has something to do with "young Fortinbras," who's apparently doing some saber-rattling at the border of Denmark and Norway.

Then Laertes asks Claudius if he can go back to France, now that the funeral for Hamlet's father, Claudius's coronation, and the wedding between Claudius and Gertrude are over. Claudius agrees to Laertes's request.

No one speaks to Hamlet for sixty-five lines. When Claudius and Gertrude finally talk to Hamlet, it's to complain about his demeanor and his clothes.

CLAUDIUS. How is it that the clouds still hang on you? (1.2.68)

Apparently, Hamlet has been carrying around his grief over his father's death.

GERTRUDE. Good Hamlet, cast thy nighted color off,
And let thine eye look like a friend on Denmark.
Do not for ever with thy vailed lids
Seek for thy noble father in the dust. (1.2.70–72)

Gertrude complains that Hamlet is acting gloomy all the time, and he's always wearing all-black mourning clothes. He's also walking around with his head down, looking dejected.

If everyone dies, Gertrude says to Hamlet, "Why seems it so particular with thee?" In other words, why is Hamlet mourning so excessively for his father?

HAMLET. Seems, madam? Nay, it is. I know not seems.
'tis not alone my inky cloak, good mother,
Nor customary suits of solemn black,
Nor windy suspiration of forced breath,
No, nor the fruitful river in the eye,
Nor the dejected havior of the visage,
Together with all forms, modes, shapes of grief,
That can denote me truly. (1.7.79–86)

Hamlet adds his heartfelt sighs and river of tears to the list of his behaviors that annoy Claudius and Gertrude, and he remarks that none of these outward shows of mourning even come close to expressing the true sense of grief that he feels over his father's death.