Lord Capulet compares Juliet to a puppet or a doll when she refuses to marry Paris.
As Juliet’s father, Lord Capulet considers it his right and duty to marry off his daughter to whoever he chooses. She is his daughter and she should follow his will. When she tells him that she does not want to marry Paris, he gets very angry. He tells her that he worked hard to find a suitable mate.
[Having] now provided
A gentleman of noble parentage,
Of fair demesnes, youthful, and nobly train'd,
Stuff'd, as they say, with honourable parts,
Proportion'd as one's thought would wish a man;
And then to have a wretched puling fool,
A whining mammet, in her fortune's tender,
To answer 'I'll not wed (Act 3, Scene 5)
By comparing Juliet to a “whining mammet,” Capulet is basically saying that she is a puppet or a doll. He is diminishing her, as if she were a worthless child. In Capulet’s mind, Juliet does not have a will of her own. She should not have the ability to choose who she marries or when. She is his to command.
Juliet, for her part, is very upset. She asks her father if he has any pity for her, and then appeals to her mother for help. Her mother, however, will not provide any assistance either.
Talk not to me, for I'll not speak a word:
Do as thou wilt, for I have done with thee. (Act 3, Scene 5)
Juliet’s father suggests that he will disown her if she does not do what he wants, and her mother refuses to speak to her. She definitely is in a pickle. Juliet cannot marry Paris because she is already married to Romeo, but she does not tell her parents this. Her father compares her to a puppet, and it is ironic because although he scoffs at her for being a puppet he actually wants her to be his own puppet. He wants her to do whatever he says. He wants to pull the strings.
Young, and in love, Juliet jumped in the situation with Romeo without really considering the consequences. Now consequences are raining down on her, and she has no choice but to take drastic action. She fakes her death, and we all know how that turns out. Romeo and Juliet both end up actually dead.
Juliet is really in a bind here, but it is one of her own creation. She married Romeo in secret, knowing that her parents would never approve and also aware that her father was actively searching out a husband for her. Juliet had to be aware that her father expected to choose the match himself, and as was the custom of the day, the match would benefit him politically. He was not expecting a love match. She also never communicates with either parent. If she had, they would not have been happy, but some of the disasters that follow might have been avoided.