The distinction between “happiness” and “blessedness” is a vital one to understanding how very far our age of Moralistic Therapeutic Deism is from Christianity. Auden explored the difference in his great poem “As I Walked Out One Evening.” Awareness of the tragic dimension of life deepens the callow expectation of happiness into an awareness of blessedness.

Gregory Wolfe, in an essay about the 20th century Catholic literary renaissance, [sorry, I'd forgotten the link in the earlier version!] has this to say about Evelyn Waugh and Brideshead Revisited:

By the end of the novel, Sebastian and Cordelia are also living stunted and sad lives. But, as happens so often in the fiction of Evelyn Waugh, a throwaway phrase contains the core of the novel’s meaning: “happiness doesn’t seem to have much to do with it.”

For Waugh, the notion that the life of faith ought to lead inevitably to worldly prosperity and what the pop psychologists call “wellness” is both unrealistic and dangerous. In a fallen world, afflicted by evil and stupidity, happiness can never be a gauge of fidelity to God. To think otherwise is to confuse happiness, with its bourgeois connotations of comfort and freedom from any burdens, with blessedness, or what Catholics call the “state of grace”.

Catholics, Waugh believed, have always clung to the foot of the cross, profoundly and intuitively aware of what the Spanish philosopher Unamuno called “the tragic sense of life”. When Julia Flyte, one of the “half-heathens”, reaches a moment of crisis in Brideshead Revisited, it is the unexpected memory of the crucifix on the wall of her nursery that shocks her into a recognition of how far she has drifted from God. As the characters in Brideshead enact their “fierce little human tragedy”, it becomes clear that they are all in some fashion struggling against God and his Church, symbolized by Brideshead Castle, that magnificent baroque backdrop to the novel’s action. Thomas Howard has spoken of the Church as the “unseen” character in the novel.

I am convinced that Waugh intended the Church to look like the “kiss of death”, not out of perversity but because he understood it to be a “sign of contradiction”. The sufferings that it seemingly inflicts, because of its laws and absolute claims, are the bitter herbs through which the disease of sin is purged. On closer inspection, the lives that the characters lead at the end of the novel, while not “happy”, are in many ways “blessed”. Sebastian is a holy fool, a drunken porter for a monastery in North Africa. When he learns of this, Charles asks Cordelia: “I suppose he doesn’t suffer?”

“Oh yes, I think he does. One can have no idea what the suffering might be, to be maimed as he is — no dignity, no power of will. No one is ever holy without suffering. It’s taken that form with him… I’ve seen so much suffering in the last few years; there’s so much of it coming for everybody soon. It’s the spring of love.”

More:

Brideshead Revisited is only one example of the ways in which the twentieth-century Catholic writers sought to recover the sense of the sacred. But in its depiction of the Church as a sign of contradiction, it fulfills Flannery O’Connor’s requirements of revealing both a drama of salvation and a way of addressing “the particular tragedy of our own times”.

The chasm of understanding between religious traditionalists (not necessarily political conservatives!) and others has much to do with a failure of the latter to comprehend the concept of blessedness, and the distinction between being happy and being good.