I have taught this constantly using words from holy Scripture. The world is not evil, because it has come from God’s hands, because it is His creation, because ‘Yahweh looked upon it and saw that it was good’ (cf Gen 1:7 ff). We ourselves, mankind, make it evil and ugly with our sins and infidelities. Have no doubt: any kind of evasion of the honest realities of daily life is for you, men and women of the world, something opposed to the will of God.
On the contrary, you must understand now, more clearly, that God is calling you to serve Him in and from the ordinary, material and secular activities of human life. He waits for us every day, in the laboratory, in the operating theatre, in the army barracks, in the university chair, in the factory, in the workshop, in the fields, in the home and in all the immense panorama of work. Understand this well: there is something holy, something divine, hidden in the most ordinary situations, and it is up to each one of you to discover it.
I often said to the university students and workers who were with me in the thirties that they had to know how to ‘materialise’ their spiritual life. I wanted to keep them from the temptation, so common then and now, of living a kind of double life. On one side, an interior life, a life of relation with God; and on the other, a separate and distinct professional, social and family life, full of small earthly realities. (Conversations, 114)
We live in a different world today. In the Middle Ages, man's relation to the Universe was altogether different. He understood his place, and he understood the goodness of Creation. There was less of a schism between the world and his soul. Today, our interior and exterior lives are lived in isolation; if we have an interior life at all.
Often Catholicism is lived in isolation, as well. We use the hostility of the world as an excuse to retreat from the world. We stand apart. I like how St. Josemaria says that "evasion of the honest realities of daily life... is opposed to the will of God." I believe that Christians should be able to hack it in the "real" world. Does that sound harsh? It may be.