Happiness is thus, to put it in Badiou’s terms, not a category of truth, but a category of mere Being, and, as such, confused, indeterminate, inconsistent (recall the proverbial answer of a German imthe “thrilling romance of orthodoxy” migrant to the United States who, when asked “Are you happy?,” answered: “Yes, yes, I am very happy, aber glücklich bin ich nicht . . .”). It is a pagan category: for pagans, the goal of life is to live a happy life (the idea of living “happily ever after” is a Christianized version of paganism), and religious experience or political activity themselves are considered a higher form of happiness (see Aristotle)—no wonder the Dalai Lama himself has had such success recently preaching the gospel of happiness around the world, and no wonder he is finding the greatest response precisely in the United States, the ultimate empire of (the pursuit of ) happiness. . . . In short, “happiness” is a category of the pleasure principle, and what undermines it is the insistence of a Beyond of the pleasure principle.
In a strict Lacanian sense of the term, we should thus posit that "happiness" relies on the subject’s inability or unreadiness fully to confront the consequences of its desire: the price of happiness is that the subject remains stuck in the inconsistency of its desire. In our daily lives, we (pretend to) desire things which we do not really desire, so that ultimately, the worst thing that can happen is for us to get what we "officially" desire. Happiness is thus inherently hypocritical: it is the happiness of dreaming about things we do not really want.
Slavoj Zizek, The Puppet and the Dwarf: The Perverse Core of Christianity