1. During Eddie's devastating death on Stranger Things, Joseph Quinn improvised "I love you, man" in the moment — which meant Gaten Matarazzo's reaction was also genuine.
2. And Lucas screaming "ERICA, HELP!" as he's holding Max was improvised by Caleb McLaughlin.
3. All of Peter's lines as he blips in Avengers: Infinity War were unscripted. Director Joe Russo just told Tom Holland that Peter didn't want to die, and Holland came up with the lines on his own.
4. And in Avengers: Endgame, the famous line Morgan says to Tony that he later repeats back to her was originally "I love you tons." Downey Jr. himself suggested Morgan change it to "I love you 3,000" as that's something his real-life children say to him.
5. In A Quiet Place, John Krasinski's character was just supposed to say "I love you" before he died. Millicent Simmonds suggested he say "I have always loved you" instead, and he went with it on set.
6. Allison wasn't supposed to tell Scott she loved him during her death scene on Teen Wolf, as she was in a relationship with Isaac. But Crystal Reed kept saying it, and they kept it in.
7. Rue and her mom fighting in the hallway on Euphoria was improvised by Zendaya and Nika King. In fact, the script just said, "Rue and her mom have a fight," but series creator Sam Levinson told them to "go at one another's necks .... as hard as you want to go."
8. Jason Segel didn't know that the show had killed off his character's father on How I Met Your Mother, so when Lily revealed the news to Marshall, Segel's reaction and ensuing line — "I'm not ready for this" — were unscripted.
9. Brooke's speech about high school in the One Tree Hill series finale was improvised by Sophia Bush, who drew on her real-life experience finishing up filming the series.
10. Helena Bonham Carter and Emma Watson came up with everything in the scene where Bellatrix tortures Hermione in Harry Potter and the Deathly Hallows — Part 1.
11. Also, Bellatrix carving "mudblood" in Hermione's skin wasn't in the script — Bonham Carter and Watson came up with it.
12. Zeek's speech to Amber after her car crash on Parenthood was unscripted. Mae Whitman said she didn't know what he was going to say and that her reactions in the scene were “totally surprised and genuine.”
13. The Priest said "I love you too" at the very end of Fleabag at actor Andrew Scott's insistence — Phoebe Waller-Bridge had considered it but wasn't sure she wanted to include it.
14. In Titanic, Jack and Rose make their way to the railing to hang on as the ship is sinking. Rose says "Jack, this is where we first met!" and Jack kisses her forehead — turns out this line was a suggestion from Kate Winslet herself.
15. One of the most famous lines from Casablanca — and, honestly, movie history — is "Here's lookin' at you, kid." Humphrey Bogart himself actually came up with the line while filming the Paris flashbacks, and the writers decided to use it a few more times in the film — including in this iconic ending scene.
16. The similarly famous "tears in rain" speech from Blade Runner was also improvised. Actor Rutger Hauer was given a much longer speech to say, but he rewrote and improvised a shorter version. In particular, he came up with the "tears in rain" line.
17. In rehearsals for her character Moira's death scene on Arrow, actor Susanna Thompson told her onscreen daughter Thea to close her eyes. Showrunner Marc Guggenheim loved it so much he told the script supervisor to keep it when they filmed the actual scene.
18. While we weren't necessarily sympathetic to Walt at this point, one of the most devastating moments for his character on Breaking Bad was when he kidnapped Holly and she called out for her mom. This happened organically on set — the child actor was calling out for her real mother and Bryan Cranston just went with it.
19. And finally, This Is Us made the bold decision not to have the audience hear the Big Three's eulogies in its finale. While that was scripted, the actors didn't know they'd still have to come up with eulogies on the spot. While we don't get to hear what they're saying, all of the acting — and the reactions from the congregation — is improvised.
