A linguistics professor says during a lecture that, "In English, a double negative forms a positive. But in some languages, such as Russian, a double negative is still a negative. However, in no language in the world can a double positive form a negative." But then a voice from the back of the room piped up, "Yeah, right."
It's funny because: "Yeah" and "right" are technically affirmative words, but put these two positives together and you get an ultra-sarcastic, "Yeah, right."
It's on this list because: It's true.