Enforced Method Acting: While shooting The Princess Bride, André the Giant was having trouble with his lines. To get him to focus, Mandy Patinkin gave him a slap. Needless to say, the entire cast and crew had a joint Oh Crap moment but it seemed Mandy knew what he was doing. Andre actually thanked him and was able to focus and get his lines right on the next take.
Method Acting: In 1972, Mandy Patinkin lost his father to cancer (and long after the film was diagnosed with and successfully treated for the same kind). He channeled his grief into playing the character of Inigo Montoya, who had also lost his father to a great evil.
Mandy: And in my mind, I feel that when I "killed" that six-fingered man, I killed the cancer that killed my father. For a moment he was alive. And my fairy tale came true.