This Karen is not prepared for the person she is harassing to stand up to her, as this guy does by just saying, "your mother," while she is calling him a "disgusting piece of crap."

It seems that this Karen is upset at the fact that this man is parked in a spot in front of their building, but she can't seem to accept the fact that he lives there too. She asks him if he has a parking pass, which he says he does, and then she says that even through she sees him all the time she knows he doesn't live there. Hmm... it almost sounds like she's wrong. She takes issue with his attitude, not that she's exemplifying a good one, and starts to berate him. Good thing he has the killer response lined up.

Her little tap-punch on the window as it rolls up is the icing on the cake to this whole interaction.