Here is what I was referring to in my coffee post: Calvin’s doctrine of vocation tends to emphasize working for the glory of God. That CAN result in doing things in isolation, a perfectionism that can be seen as “doing something for God,” possibly degenerating into a kind of work righteousness (as opposed to “works righteousness”). It CAN degenerate into scorn and ill-treatment of those human beings who are actually around us, resenting family members or customers for getting in the way of our work.
Luther, on the other hand, emphasized that vocation does not presume to serve God; rather, it serves our neighbor. Actually, God Himself serves our neighbor through our hands when we work in our callings. Thus, the focus in vocation must always be on the neighbor whom we are to love and serve.
Of course, we are to both glorify God and serve our neighbors, not playing these off against each other. The way God commands us to glorify Him is precisely to love and serve our neighbors, so these are not really in opposition. And, as was said, loving and serving our neighbor should include giving him the very best we can, and not just fulfilling him his possibly unworthy desires.
Right, we don’t know whether or not the barista in question is a Christian whose obsession with excellence was motivated by a desire to glorify God. I have, however, known Christians who pursued their work out of a religious motive but without regard of their neighbors. Also, there is no reason why Luther’s emphasis could not be shared by someone of some other theology, though his notion that God usually works through means–and ordinary, physical means at that–might not be accepted by hyperspiritual theologies.