2 The Dark Knight (2008)
In one of the film's most pivotal scenes, where Joker blows up a hospital, Heath Ledger is not given lines to show his reaction when the detonation appears to suddenly go haywire.
Ledger portrayed the anarchic Joker who pressed the detonator, which did not explode as it had a technical problem, and he fidged with the detonator in frustration before it finally blew. His surprise, mixed with Joker's reaction, with the mad laughter of his own, perfectly suited to the unconventional volubility that characterises him, locked the frame into chaotic energy.
Ledger's quick thinking wraps up one of the best moments of the movie, showing how completely he had sunk into the character, adding to the mythos of his characterization of Joker.