No semi-civilized person has ever served tap water to guests (particularly well-heeled Los Angeles guests) at a dinner table. Ever. But if they did happen to do this…well, I wouldn’t react the way Larry David does in this clip. After tasting it, I would simply return the nearly-filled glass of tap water to its proper position and innocently ask my host if he/she happens to have…oh, a Diet Coke or Ginger Ale or something in that realm. That’s why this bit doesn’t quite work. Because the Elizabeth Perkins character isn’t based upon reality.
And anyone who equates the throwing of a softball or the swinging of a tennis racket to stabbing a dummy with a carving knife isn’t eccentric or whimsical or loopy — that person would be psychotic.