What’s the problem with Romeo and Juliet?

I believe that in Romeo and Juliet, the problem is the hatred between the two families of Montague and Capulet. Because of their enmity, it turned out that Romeo and Juliet died because they were children of families that were at war. If the families were not at odds with each other, then I am sure that the ending would be happy. When families saw their children dead and learned that they loved each other, the families reconciled in the name of remembering their children. But the love of Romeo and Juliet will live forever.