Eccl. 2:2. I said of laughter: It is mad, and of pleasure: What use is it?
You should take all these things as referring to human counsels. He wants to say: “I wanted to use skill to seek the good, to seek pleasures and happiness. But this thought was sheer madness, which brought me double affliction. In the first place, the very labor of thinking and seeking brings affliction to the heart. In the second place, when I was hoping that I had achieved it, suddenly there came another conflict or trouble, and I lost both the labor and the joy.” By “laughter” he means what I myself seek, and by “pleasure” what I try to accomplish. What use is it? “Because it never turns out right for me, and some kind of trouble always arises.” Therefore the best happiness and gaiety is that which is not sought but is offered unexpectedly by God without your caring or planning. Thus outward happiness is indeed a good thing, but only for those who know how to use it well. The wicked, by contrast, even when they are lost in revelry, still are not happy, because they do not recognize that this is a gift of God and are always bored, dissatisfied with the things that are present and looking for something else. (Luther’s Works, v.15 p.331-320)