What is the role and significance of family in Romeo and Juliet?

In William Shakespeare's tragedy Romeo and Juliet, family plays an important role in motivating characters' actions, conflicts, and choices. 

Romeo and Juliet belong to two different families of the noble class living in Verona. The families have been engaged in a feud for as long as anyone can remember, to the point that everyone has forgotten the initial cause of the feud. As such, family is first and foremost associated with conflict and with loyalty. One does not choose one's side in this conflict; one is born into one side or the other. It is expected that each member of the family will participate in the feud on his or her designated side based solely on family loyalty. 

In Juliet's case, family also develops some of the true complexities of parent-child relationships. The Capulets only want the best for their daughter, including marriage prospects, and as such they push her into making certain choices. In doing so, they do not consider Juliet's preferences, trusting that they know what is best for their daughter. The result is that Juliet is driven to lie, by omission or directly, leading to conflict and ultimately to tragedy for the family.