In the scene where Roy L. Fuchs (Jack Warden) walks up to Rudy Russo (Kurt Russell) and Jeff (Gerrit Graham) as they are finishing shoveling dirt over the spot where they buried Luke, Graham didn't have any lines and kept pestering Robert Zemeckis and Bob Gale for lines. Finally, he just decides to repeat whatever Russell said to Warden. Apparently, Warden was unaware of what Graham was doing, thus his line "What're you? A fuckin' parrot?". It was Warden's genuine annoyance at Graham, which worked so well in the scene that it was included in the final cut.