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."
A Help desk guy speaking to a lady user... Help desk: Double click on "My Computer". Lady: I can't see your computer... Help desk: No... click on "My Computer" on your computer. Lady: How the hell can I click on your computer from my computer?! Help desk: There is an icon labelled "My Computer" on your computer... double click on it... Lady: What the hell is your computer doing on my computer?