That moment when DeNiro realizes he has to go after Waingro. He's not a romantic hero, he's a small-minded man of violence driven not by ideals or esoteric codes but by the basest of human urges.
That moment when Pacino practically dances down the hospital stairs, gleefully fleeing his family for the sake of the chase, freed from the pretense of normalcy, from the obligation to care about anyone else.
The tragedy and joy of learning that you cannot escape your fate, that you cannot be anything other than what you are.
Other Mann films are more romantic: the heroes of Mohicans and Blackhat see everything around them destroyed and disappear into the wilderness, but together. Miami Vice fuses the romantic and the tragic: the lovers are kept apart, but by the nature of their world, not by choice.