Given he's one of the greatest screenwriters and directors of his time, it's no surprise that Quentin Tarantino excels in several areas of filmmaking - the non-linear storylines, blending of genres, and intentionally curated soundtracks.
The thing he's most renowned for, though, are his characters.
Every one of Tarantino's characters has a distinctive voice. You care about them, love them, hate them.
All because they seem real. What they say seems natural, like it's precisely the type of thing the character would say.
“I am a writer. That’s what I do. It’s a writer’s job not just to write about himself but to look at the rest of humanity and explore it—other people’s way of talking, the phrases they use. And my head is a sponge. I listen to what everyone says, I watch little idiosyncratic behavior; people tell me a joke, and I remember it. People tell me an interesting story in their life, and I remember it.” - Quentin Tarantino
When dialogue seems real, the story feels authentic, and the audience gets lost in the film.
The opposite is also true.
Bad dialogue is like fingernails scratching on a blackboard. It makes you cringe. You naturally pull away from the story, aware you're sitting in a theatre waiting for the next bad line.
Even though we know this is a fictional world, we can't lose ourselves in it because it doesn't feel real.
Anakin: “You are so beautiful”
Padme: “It’s because I’m so in love with you.” - Star Wars, Revenge of the Sith
Star Wars, Revenge of the Sith
Your copy is your dialogue.