George C Scott won Best Actor for Patton and refused it, having declared beforehand that he considered the ceremony a meat parade. He was the first actor to decline the award.
Patton opens with a six-minute monologue delivered directly to camera in front of an enormous flag, and Scott plays the man as both magnificent and impossible, which is the only honest reading.
Dr. Strangelove gives him a wholly different mode. Kubrick reportedly obtained the broad performance by telling him the exaggerated takes were rehearsals and then using them.
The Hospital and Hardcore are the underseen ones, and he directed several films himself, including Rage.