NO ANSWER (IS IT BECAUSE OF EGO)
When I don't have an answer or an appropriate answer to the question posed to me, then I try to find a way to escape from the situation. The best responses that I give are:
That is the way it is supposed to be...don't start an argument. - or
That is it, do not question the basics of life (or whatever the topic is about.) It is only the foolish who harp on such issues. - or
You don't know this simple thing is it...oh god, you should improve your knowledge. - or
Oh you know it, but just pretending you don't know. And since I know that you know, let us leave the topic.
(hmm anymore to add...oh help me out...I sure could do with some more responses.)