There are quite a few candidates for theme or moral in this story. Here are my two top themes or morals.
- One moral is that selfish behavior is bad. The Capulets and Montagues hate each other for selfish reasons (we don't know why they do, but clearly they are being unreasonable). Their behavior leads to the death of Romeo and Juliet.
- One major theme is the importance of fate. We are told early on that Romeo and Juliet are "star-crossed." No matter what they try, it goes wrong. Romeo tries to make peace with the Capulets but that allows Tybalt to kill Malvolio and that makes Romeo kill Tybalt. Friar Lawrence comes up with a plan for Romeo and Juliet to be able to be together, but it leads to both of them dying.
So, these are a couple of themes/morals. Other people may have other ideas.
In the play 'Romeo and Juliet' by William Shakespeare, on of the most prominent themes is suggested by the quote 'a plague on both your houses.' The moral relating to this is that it is wrong, dangerous,pointless and counter-productive to bear grudges - particularly ones that ocurred so far back in time as to be history themselves, the original reason forgotten about. yet, the damge they do casts its shadow forward in time to influence wars, hatred,atrocities and even the emotional well-being of descendants hundreds of years later (such as the innocent children Romeo and Juliet.) Riots and public disorder have wreaked havoc in the towns of the Montagues and the Capulets as rival factions squabble and disturb the peace. The Prince is angry, and blames both,almost bringing down a curse on the families if they don't stop - Romeo and Juliet are lost to their families and die becuase of the pointless hatred between them.