|Summer volume of the Breviary of Renaud/Marguerite de Bar, Metz ca. 1302-1305.|
Verdun, Bibliothèque municipale, ms. 107, fol. 105r
I'm not saying we should not enjoy and value happiness. But I find the hype of constant happiness exhausting. Perhaps I should distinguish between bubbly, consumptive happiness between deep and abiding peace, or even joy. The former can't seem to survive in the face of reality, while the latter is more stable.
I remember reading Aquinas's Summa Theologica in college, and our professor telling us that Aquinas believed that God's plan for humans was happiness. I still like that idea, but the key is understanding what Aquinas meant by happiness, and taking from it what you will. I think it's so easy to fall into a search for enjoyment (which of course has its place) in our current times, rather to search for something greater:
"Man’s ultimate happiness consists in the contemplation of truth, for this operation is specific to man and is shared with no other animals. Also it is not directed to any other end since the contemplation of truth is sought for its own sake. In addition, in this operation man is united to higher beings (substances) since this is the only human operation that is carried out both by God and by the separate substances (angels)."
—Summa Contra Gentiles, book 3, chapter 37
If you're not a fan of this version of psychology, you might take a look at Slavoj Zizek's critique of the superego's mandate of enjoyment.