...lies, all the devil's wicked lies

I don't normally lie, but sometimes I get this urge to lie for no reason. To lie when it won't really make a difference to anyone around me if I tell the truth. Usually, someone will tell me something, or ask me something, and immediately my mind will fabricate this answer which just isn't the truth. And I want to say this answer. I'm not sure exactly what it is, but this happens maybe every week or two. When I get the urge, it also seems to crop up a few times in the same day or two. Maybe it's not that often, but it's happened recently. Unfortunately, I can't remember the circumstance. Why would I want to lie for no reason?