Quote Originally Posted by francisstokes
(not meant to be taken the wrong way) Why is that?
Not taken the wrong way at all.

Throughout the Windows interface, when the user requests an action and a confirmation dialogue box is displayed, the OK, Cancel, Yes and No buttons have specific meanings. OK means "do what I asked", Cancel means "don't do what I asked", Yes means "do what I asked plus something extra", No means "do what I asked but nothing extra". Take note of the dialogues that Microsoft products display and you'll see that whenever you are asked a question like "Are you sure you want to..." the buttons on the dialogue will be OK and Cancel. An appropriate use of Yes and No would be if the question was "Do you want to save your changes before exiting?" where Yes would mean save and close (do what I asked plus something extra) and No means close without saving (do what I asked but nothing extra). The fact that No and Cancel mean different things is evidenced by the fact that there is a Yes, No, Cancel button combination. You could use it in the previous example where Cancel would mean don't close (don't do what I asked). That demonstrates the difference between No and Cancel very clearly.

Of course, there are other situations where Yes and No are appropriate, like if you were asking "Do you live in the United States?". I'm talking specifically about when the user requests an action and your message box is confirming that action.