R. Lee Ermey

Originally brought on to Full Metal Jacket for accuracy advice, his demonstrations of how to do a Drill Sergeant Nasty were so good that he was cast in his famed role.

Said demonstration was unflinchingly chewing out the camera with both tennis balls and rotten oranges being thrown at him, and he continued to chew out the camera for fifteen straight minutes, during which he never once moved, changed his expression, or repeated himself.

R. Lee Ermey – Television Tropes & Idioms (via merlin)