Like a madman who throws fire brands, arrows and death,
Is the man who deceives his neighbor
And says, “I was only joking!”
Having a truly crazy person is a great liability. A person who fully and completely lacks all sense of sanity becomes a danger to himself and others in very short order. That person may become even more dangerous should he be supplied with weapons. Imagine going into battle with a person who is meant to be on your side, only to find that person firing indiscriminately and taking out his own men. This is the image which the Bible uses to explain a person who lies for a joke. C.S. Lewis pointed out in the Screwtape Letters what a marvelous tool this is on the part of the Satanic influence upon earth. A person can be cruel, a person can be selfish, a person can be dishonest but if it is framed as a joke it is supposed to be just fine. There is a great place for humor, but there is also a way to use humor as a weapon of destruction.