REVEREND CLAYTON: You wanna quit, Ethan?
ETHAN: That'll be the day.
MARTIN: I hope you die!
ETHAN:: That'll be the day
The Searchers (1956)
In the above movie, Ethan Edwards (John Wayne), a hardened, embittered Civil War veteran, and his adoptive nephew Martin Pawley (Jeffrey Hunter), spend years searching for Ethan's niece who was abducted by Indians. Regarded today as a classic and one of the best Westerns ever made, it received not one Academy Award nomination.
Whenever someone says something to Ethan, or makes a suggestion him, with which he does not agree, Ethan responds with "That'll be the day." Buddy Holly was so influenced by seeing that movie and hearing the line that he wrote his hit "That'll Be the Day". The 1960's pop group The Searchers (Sweets for My Sweet, Needles and Pins, When You Walk In the Room, Sugar and Spice, Don't Throw Your Love Away, Love Potion No 9) took their name from the movie.