White Heat with James Cagney contains two of the greatest scenes in all of film, not just the gangster movies.

Cagney as Cody Jarrett is eating lunch in the prison cafeteria when word arrive that his mother is dead. The word is passed from a trustee to each prisoner down the table until the last unfortunate soul has to tell the psychotic Jarrett. Cagney goes berserk, kicking food off the tables, screaming, punching guards and inmates.

The second scene is the great one where Cagney takes refuge from the police at the top of a fuel storage tower. He is shot multiple times and staggers around the platform, bloody and laughing hysterically. At last, he fires his pistol into the leaking fuel, shouting "Look Ma! I'm on Top of the World!" And then the whole tower explodes in a fireball.