Juliet and the nurse.
Their relationship is like mother and daughter, the nurse has and will always be there for Juliet and Juliet will always seek approval and support from the nurse throughout her life. The nurse cares about Juliet more than Juliet's mother and father, she cares about Juliet's happiness as well, which doesn't include marrying Paris and she will always love Juliet as if it was her own child.
Juliet always goes to the nurse for advice and looks at her as the motherly figure she has always wanted, but never had. In act 3 scene 2 after Romeo kills Tybalt and is banished, the nurse was still supportive of Romeo and Juliet's love, so she agrees to go find Romeo to comfort Juliet.
"Hie to your chamber. I'll find Romeo to comfort you: I wot well where he is. Hark ye, your Romeo will be here at night: I'll to him; he is his at Laurence' cell."
Unhealthy:
Capulet and Juliet.
Their relationship is not at all what a functional father daughter relationship is supposed to be like. The father is supposed to support his daughter in her decisions, but guide her at the same time. Capulet made no effort in accepting Juliet for the way she is and what she wants for herself. Juliet didn't care about Paris wether he had money or not and Capulet shouldn't have gotten angry with her when she didn't accept his hand in marriage.
Yes, Capulet did tell Paris that Juliet is a little bit young to be getting married and told Paris to try and get Juliet to actually like him before they got married, but still that's not being considerate of her feelings that's making sure he doesn't have to listen to her whine about how she doesn't want to marry Paris anymore. He doesn't want to be a father to her, he wants to control her and the future of his family line and to do that, he will do whatever it takes.
After Tybalt's death Capulet and Paris discussed what day Paris and Juliet will be married and decided to do it on the Thursday, so Capulet told Lady Capulet to tell Juliet when her wedding is. After Lady Capulet told Juliet, Capulet asked about what she said and Lady Capulet told him that Juliet didn't want to get married to him and his response was,
"Hang thee, young baggage! disobedient wretch! I tell thee what: get thee to church o' Thursday, Or never after look me in the face: Speak not, reply not, do not answer me; My fingers itch. Wife, we scarce thought us blest That God had lent us but this only child; But now I see this one is one too much, And that we have a curse in having her: Out on her, hilding!"
Basically he is saying that he wishes she wasn't born because she is disobedient and disappointing because she won't marry Paris as he wants her to so he can make his family line better off and she is the only thing stopping him.
To Shakespeare, the type of relationship that the nurse and Juliet had was probably the most common because back in that day in age every higher end family would hire a nurse or a nanny to take care of the children and to pretty much raise them while the parents continued on with normal lives and hosted a lot of parties. Even though Shakespeare wasn't on the highest level of social standing, he probably still thought that it was a normal thing to see a nurse act as a mother to the children from birth, especially when, as a lower class person, you tend to notice or pay more attention to how people higher than you in social class are living their lives and doing things.
