The significance - and ultimately the quality - of the work we do is determined by our understanding of the story in which we are taking part. If we think of ourselves as merely biological creatures, whose story is determined by genetics or environment or history or economics or technology, then, however pleasant or painful the part we play, it cannot matter much. Its significance is that of mere self-concern. "It is a tale / Told by an idiot, full of sound and fury, / Signifying nothing," as Macbeth says when he has "supp'd full with horrors" and is "weary of the sun."
If, on the other hand, we believe that we are living souls, God's dust and God's breath, acting our parts among other creatures all made of the same dust and breath as ourselves; and if we understand that we are free, within the obvious limits of mortal human life, to do evil or good to ourselves and to the other creatures - then all our acts have a supreme significance.