Why does Romeo and Juliet have a lot of offer in the 21st century

There are two basic approaches to what caused the tragedy in Romeo and Juliet:
1. The warring Capulet and Montague parents, too wedded to their ancient grievances, were unwilling to listen to what their children wanted, which led Romeo and Juliet to kill themselves rather than be apart;
2. Romeo and Juliet themselves, despite being only teenagers, were so swept away by their whirlwind romance that they acted rashly in the belief that they were really in love, rather than listening to common sense from those around them.
The first interpretation is the more romantic one, and what it teaches us in the 21st century is that we should not allow issues such as class or race to come between two people who are in love. The Capulets' and Montagues' dislike of each other is based largely on prejudice; Romeo himself has done nothing to offend. Prejudice cannot end well.
The second interpretation is relevant to 21st century audiences too. Romeo and Juliet is often taught in schools when students are 13 or 14, the age Juliet is stated to be in the text. 13 is old enough for us to feel as if we're adults, but once we reach 20, we realize how young 13 really is. If Romeo and Juliet had not been so wedded to a "love" based on nothing more than a few conversations and kisses, the situation would not have escalated as it did. So, the play can be read as a cautionary tale about the dangers of acting too rashly as a teenager, when emotions run high but attachments often do not last.