Movies are forever. Movie scripts, on the other hand, are hardly set in stone. Throughout the history of cinema, some of the best, most iconic lines that ever existed were created on the spot, delivered accidentally, or made up by the inventive minds of Hollywood actors.

There’s no shortage of iconic improvised lines in this compilation, from Orson Welles’ The Third Man to Walt Disney’s Frozen! And some of these are so good, clever, and memorable that it’s almost unbelievable to think they were never part of plan A. Has your favorite film made it to the list?

“You Can’t Handle the Truth!” (A Few Good Men)

With Jack Nicholson, Tom Cruise, and Demi Moore in the leading roles and Aaron Sorkin as the screenwriter, the 1992 drama A Few Good Men was bound to be good. The movie did make a huge impact, but it’s still hard to believe that one of the best lines in the entire film was made up on the spot by Nicholson.

The script read: “I want the truth!” but Nicholson wasn’t a big fan of the line. So he changed it a little bit, coming up with the more impactful “You can’t handle the truth!” It fitted perfectly within the plot and Nicholson’s character, the self-entitled Colonel Nathan R. Jessup.

“It’s Such a Fine Line Between Stupid and Clever” (This Is Spinal Tap)