It is an isolating condition, cutting us off from receptiveness towards God and others. We can never find joy apart from loving what is truly good. Ultimately, we will never have joy unless we have union with god, Happiness Itself. As understood by the saints, it is not laziness about life's affairs, but rather an aversion to and a negation of spiritual things. It reveals itself in an undue concern for external affairs and worldly things.
Acedia is spiritual torpor, an absence of zeal for divine things.
And it brings with it, according to the ancients, a sadness, a weariness of the world. The slothful person hates the spiritual, and wants to be free of its demands. It eventually leads to a hatred of the good altogether. And with hatred comes more rejection, more ill temper, sadness, and sorrow. He finds their views remarkably coincident.