There's a special kind of magic that happens when actors get so into character that they can manage to give the writers a little boost—by improvising lines that fit perfectly with the character and scene.
Some of the best and most iconic movie scenes, moments, and lines actually weren't written in the script. Indeed, these are the times that prove how valuable an actor can be.
We all have our favorites, but here are our picks for the best unscripted movie scenes, moments, and lines that stick with us.
5. "I don't want to go" (Avengers: Infinity War)
There are some real standout performances in Avengers: Infinity War, but now that more than three years have passed (as of this writing), we can talk about this scene without worrying too much about spoilers.
This is the iconic scene that showcases the full depth of the Avengers' failure in stopping Thanos. As heroes from across the universe crumble into dust, Spider-Man (played by Tom Holland) stumbles toward his mentor Tony Stark before flaking away.
In the scene as written, Spider-Man was only supposed to say "I'm sorry" to Tony Stark, but the directors felt it didn't pack enough punch to break viewers' hearts—so they asked Holland to try improvising.
The result is what we got, with Holland perfectly showcasing what makes Spider-Man such a special hero: despite his power and responsibility, he's still just a scared, insecure, and overwhelmed teenager.
4. "I know" (The Empire Strikes Back)
There are few romances more iconic than that of Han Solo and Princess Leia in Star Wars. Watching their relationship grow over the course of The Empire Strikes Back was one of the lighter points in a dark film.
It all culminated in this iconic moment in Cloud City, where Han is about to be frozen solid and shipped to Jabba the Hutt for his crippling debts, when all of the sudden Leia professes her love for Han.
In the original script, Han was meant to say that he loved her too, but Harrison Ford changed it up on set. By delivering the iconic "I know" reply, he perfectly summed up the calm and collected cool of Solo who's level-headed even when he's about to be frozen for eternity.
3. "Here's looking at you, kid" (Casablanca)
We could write a whole article just on the quotes in Casablanca—which is often cited as one of the most quotable films of all time—but this one deserves special attention because it wasn't in the original script.
The iconic line was delivered at the emotional climax of the film, as Rick convinces his former lover Ilsa to get on the plane to safety. He comforts her as she begins to cry and casually delivers the line.
Humphrey Bogart (who played Rick) would teach Ingrid Bergman (who played Ilsa) how to play cards between takes and would say this line to her during these card lessons.
Since the movie's script was constantly in flux, Bogart added the line during one take—and the director enjoyed it so much that he left it in, creating one of the most iconic unscripted movie lines.
2. "What an incredible Cinderella story" (Caddyshack)
Bill Murray has always been one of the best when it comes to improvising dialogue, and this one in Caddyshack is one of his finest improvisation moments ever put on film.
As the unpredictable groundskeeper of the golf course, Murray gives one of the most memorable performances of his career without even being in the starring role, by combining his trademark sardonic wit with physical comedy that contrasted well with the rest of the film.
This monologue is completely adlibbed by Murray. The script only said that his character was outside cutting the tops off of flowers with a grass whip, but Murray delivered the entire story of himself winning the green jacket at The Masters in one unbroken take.
It quickly became one of the best moments of the film because it was something that connected every sports fan to the antics of Carl Speckler.
1. "Funny how?" (Goodfellas)
Goodfellas might just be the best gangster movie of all time, and this moment early in the film showcases the dynamic between Joe Pesci's Tommy and Ray Liotta's Henry for the rest of the movie.
As Tommy tells a story, he has everyone in hysterics with his genuinely funny delivery—then quickly turns threatening when he demands to know what Henry means when he calls him "funny." The way everyone tenses up shows how afraid they are of Tommy's constant mood swings.
This interaction wasn't originally in the script. Pesci liked to tell the story about the time he called a member of the Mafia funny while he was working as a waiter, eliciting a similar response to what we see in the film.
Director Martin Scorsese immediately thought it would fit with Pesci's character and had the cast improvise the scene during rehearsal before officially adding it to the film.