Reality.

The man who fears to be alone will never be anything but lonely, no matter how much he may surround himself with people. But the man who learns, in solitude and recollection, to be at peace with his own loneliness, and to prefer its reality to the illusion of merely natural companionship, comes to know the invisible companionship of God. Such a one is alone with God in all places, and he alone truly enjoys the companionship of other men, because he loves them in God in Whom their presence is not tiresome, and because of Whom his own love for them can never know satiety.

Thomas Merton