First, James Dean — duh. His performance is equal parts charming and absolutely gutting. He is so beautifully vulnerable and yet unbelievably cool. Everyone should watch this to understand why his legend lingers.
Second, it tells an American story that anyone can relate to. There's just something traumatizing about being a teenager, and this movie really captures the challenges of being an outsider and not relating to an older generation that wants to buy you happiness but not sit down and get to know you. It might be set in the '50s but the themes resonate still.