1)
random guy-"Hey fat-fat I can't believe you're such a loser!"
the fat-fat-"...Where do you keep your knives?"
2)
random guy-"Hey fat-fat how many fat-fats does it take to screw in a lightbulb..."
fat-fat-"Um... I don't know"
random guy-"I don't remember how the joke ends, but people hate you"