Schopenhauer called the ontological argument for the existence of God a "charming joke". What a charming way of putting it!
Some may think being a charming joke is not that bad for a philosophical argument; at least it is not as bad as just being a joke. However, when a philosopher gets carried away by his cleverness and produces a philosophical argument that is nothing but a charming joke, he may never be able to see that it is nonetheless still a joke simply because it is charming and because the charm is a result of his cleverness. For this reason, a charming joke is worse.