Coming up with a great comeback line isn’t as easy as simply figuring out a great insult. It’s also about delivery, emotion, wit and many other factors.
Also, keep in mind that your quote has to be a genuine comeback line, said by one character after the other character already had their say. So it can’t be Ripley’s “get away from her, you bitch!” cause the alien didn’t say anything prior. It also can’t be from a TV show (movies only).
Believe it or not, I’ve given this a “stupid” amount of thought, so allow me to go first with my absolute best comeback line in movie history.
Movie: Kill Bill Vol 2; Actor/Character: Uma Thurman/The Bride/Beatrix Kiddo; Scene: The Bride fights Elle Driver, who goes on a monologue about how she killed Beatrix’s master, concluding with how “in the imediate future”, Beatrix’s sword will become her sword.;
Line: “Bitch… you don’t have a future.”
That right there is 10/10 in terms of delivery and overall wit.