This was one of the two scenes that convinced Steve Martin to make the movie. Every F-bomb in Neal’s tirade was written by John …

This was one of the two scenes that convinced Steve Martin to make the movie. Every F-bomb in Neal’s tirade was written by John Hughes, not improvised. Martin delivered 18 of them in under two minutes. The scene alone earned the film its R rating. Without it, the film would have been PG-13. Edie McClurg, who plays the rental agent, is best known as Principal Rooney’s secretary in Ferris Bueller’s Day Off, another John Hughes film. Hughes told her to improvise a fake phone conversation about Thanksgiving while Martin waited at the counter. For the first few takes she had a standard call with a customer. Then Hughes told her to make it a personal call. That is when she came up with the marshmallows and the crescent rolls and «You know I can’t cook.» When Hughes asked how she came up with those lines so quickly she said she drew it from her own life, just like he does with his scripts. He said: «Oh yeah.» Her final line, delivered with a smile after sitting through Neal’s entire tirade, is three words. Roger Ebert called it the best ending to a comedy scene he had ever seen. McClurg claims people still stop her on the street and ask her to say it to them. Both Steve Martin and John Candy considered it their favorite of their own films. Film: Planes, Trains and Automobiles (1987)