* The intensity and depth of his performance: Ledger's portrayal of the Joker was unlike any other on-screen villain. He captured the character's unpredictable nature, chilling sense of humor, and utter lack of empathy with a raw intensity that was both captivating and terrifying.
* The tragedy of his passing: Ledger tragically passed away just before the film's release, adding an extra layer of sadness and poignancy to his performance. His performance became a testament to his talent and dedication, leaving a lasting legacy.
* The film's themes of chaos and darkness: "The Dark Knight" explores complex themes of good vs. evil, morality, and the nature of chaos. Ledger's performance as the Joker embodies the film's central themes, making it difficult to watch without feeling a sense of unease and even sadness.
It's completely understandable why many people cried while watching the film. Ledger's performance was a powerful and haunting experience that left a lasting impression on viewers.