“Soylent Green is people!” – Soylent Green
While the film and the novel it was based on, Harry Harrison’s Make Room! Make Room!, differed quite a bit, the original screenplay by Stanley R. Greenberg does not end with the revelation of cannibalism. Heston, feeling the movie needed a big reveal like The Planet of the Apes a few years earlier, came up with the line and had to fight director Fleischer over its inclusion.
“Luke, I am your father.” – Star Wars: The Empire Strikes Back
According to George Lucas, bodybuilder David Prowse, who was the guy wearing the Darth Vadar suit, came up with this on the spot. “It was great. I was just like, ‘Let’s go with it’ and we had to have James [Earl Jones] fly back to record the line.’
“I see dead people.” – The Sixth Sense
On the audio commentary for the film, writer-director M. Night Shyamalan states, “Haley didn’t tell me what he going to do and he didn’t tell Bruce. That’s a genuine look of shock on his face. [laughs] Kids do say the darndest things, and in this case it worked out for the best.”
“There’s always one.” – 12 Angry Men
Henry Fonda’s Juror #8 was originally going to vote guilty. Believing it would add actual drama to the proceedings, director Sidney Lumet told Fonda in private to be the one juror who voted opposite the group, surprising the other eleven actors as well as the crew on set. Ed Begley’s “there’s always one” comment was actually in reference to how there’s always one actor who goes off script and lengthens the day’s shoot.