A couple weeks ago I went to a Shabbat meal at a certain Chabad family. At one point, two of the guests got into a disagreement about what their Rebbe said or did about a particular subject. One of them asserted something, and the other responded, "That didn't really happen - it happened in ruchniyus."*
What a great response! Whenever I want to be polite in pointing out that somebody's idea is nonsense, or when they insist on taking literally something which should really be taken allegorically, I now have the perfect answer. "What you are saying is true, but only in ruchniyus." I can't wait to use it.
*That is to say, it's "spiritually" true, even if not factually true.