Most of the great filmmakers in American cinema will candidly admit some of the most enduring and memorable moments in their films were scenes or lines that were never in the script.

“Here’s looking at you, kid,” was never in the “Casablanca” script, it was a Humphrey Bogart ad-lib. “Leave the gun. Take the cannoli,” from Francis Ford Coppola’s “The Godfather” was a riff from the actor. On a lighter note, the iconic scene in “Pretty Woman” when Richard Gere snaps a jewelry box on Julia Roberts’s fingers was originally a practical joke.