Happiness and joy are not the same. For what does the fervent craving for joy mean? It does not mean that we wish at any cost to experience the psychic state of being joyful. We want to have reason for joy, for an unceasing joy that fills us utterly, sweeps all before it, exceeds all measure.
... each gratification points to the ultimate one, and that all happiness has some connection with eternal beatitude. Some connection, if only this: that every fulfillment this side of Heaven instantly reveals its inadequacy. It is immediately evident that such satisfactions are not enough; they are not what we have really sought; they cannot really satisfy us at all.