What are some of the qualities of the nurse in Shakespeare's Romeo and Juliet and why are they important to her character?

The nurse is incredibly loyal and loving to Juliet, though not particularly intelligent. She still seems to think of Juliet as a child, as she fails to recognize the strength of Juliet's devotion to Romeo.  With the nurse, it seems that what you see is what you get, and her loyalty to Juliet allows the love between Romeo and Juliet to reach fruition when she agrees to be their go-between.  Juliet depends on her and trusts her implicitly, at least until she advises Juliet to marry the County Paris after Lord Capulet threatens to throw her out if she disobeys him.  Even then, however, the nurse is trying to advise Juliet as she thinks best, but it is that crucial moment -- when she fails to recognize the strength of Juliet's loyalty to Romeo -- that severs something between them.  If the nurse were a little smarter or understood the strength of Juliet's loyalty to Romeo a little better, she would have advised her differently and not completely alienated Juliet.  The tragedy of Romeo's and Juliet's deaths might have been averted if the nurse had not sided with her father.