Why would someone consider Romeo and Juliet a timeless classic?

Since it is a story that has been told, adapted, and read by millions of people for hundreds of years, I would say that makes it "timeless." It contains universal themes that are relevant to every generation and even across cultures. Themes like family grudges, young people in love, love/relationships that are doomed from the start.

Because it is taken directly from the Greek tragedies written in 400 BCE about star-crossed lovers, be then mother and son, or two fourteen-year old Veronans with the wrong surnames whose parents are enemies. This line for a play goes back to old Mycenae, Greece, and before that to Egypt (man) versus Nubia (woman) (which became the opera, Aida). The theme always is star-crossed lovers, Romeo and Juliet, Arab Sheik and Jewish nanny, Black Mandingo and white slave holder, or any other opposites who attract against all odds of family protest--even Fiddler on the Roof--traditional Jewish daughter with red hair marries Christian Russian peasant man with blonde hair, and so on.

I suppose because most of us were drama queens in our teens.

Just like Romeo and Juliet.

Read the section on "Romeo and Juliet" in Richard Armour's "Twisted Tales from Shakespeare" (excellent book, very funny).

because people still read it, it's a tragic love story. shakespeare was awesome, and his writing has lived on. Romeo and Juliet is also a tale about bad parenting, and that pushing your children only makes them do what you don't what them to.

because it is one of the only good books that expresses young love. The themes are universal, the message is timeless, and the dialogue is beautiful.

Because it is a testament to true love