How to make witty comebacks in ten seconds: When someone gives you shit, you give them shit, or make fun of them giving you shit. Don’t hold back: If you wait, the moment is gone.
Example: “Dangit Django, why’re you leaving your garbage in the way?” Correct answer: “I left them just for you! Do you like it?”
And remember, be sure to let them know it’s a joke. Unless it’s not, and you hate their guts.