when I screw with them. I repeat the complete opposite back to them of whatever they just said. So if they say they are going to arrange shipping to have it picked up. I reply back, "so you will be here to personally pick up the item". "And you said, you will bring cash in hand" I'll wait for your arrival.

Then when they correct you. Reply the same thing back and act like you can't understand the terms they want. They get soo pissed. Especially when they think they have you on the line and setup.