There’s a lot more to acting than memorizing lines and nailing them once the cameras start rolling. In fact, it may surprise you to know that some of the most iconic TV moments, from Brooke’s heartfelt monologue at Tree Hill High to Eric’s classic Feeny call on Boy Meets World, are actually improvised. And no, it’s not always because someone happened to slip up on their lines (although that has definitely happened). In most cases, they’re spur of the moment actions that elicit more genuine responses from characters—and even better, these ad libs can be so profound that they inspire the screenwriters to change the story’s (or episode’s) entire outcome. Talk about impressive!
From Buffy the Vampire Slayer to Friends, here are 20 iconic improvised scenes from TV shows.