From Pope Benedict's homily for the Immaculate Conception in 2005:
“...we have a lurking suspicion that a person who does not sin must really be basically boring and that something is missing from his life: the dramatic dimension of being autonomous; that the freedom to say no, to descend into the shadows of sin and to want to do things on one's own is part of being truly human; that only then can we make the most of all the vastness and depth of our being men and women, of being truly ourselves; that we should put this freedom to the test, even in opposition to God, in order to become, in reality, fully ourselves.
In a word, we think that evil is basically good, we think that we need it, at least a little, in order to experience the fullness of being. We think that Mephistopheles — the tempter — is right when he says he is the power "that always wants evil and always does good" (J.W. von Goethe, Faust I, 3). We think that a little bargaining with evil, keeping for oneself a little freedom against God, is basically a good thing, perhaps even necessary.
If we look, however, at the world that surrounds us we can see that this is not so; in other words, that evil is always poisonous, does not uplift human beings but degrades and humiliates them. It does not make them any the greater, purer or wealthier, but harms and belittles them.
This is something that we should indeed learn on the day of the Immaculate Conception: the person who abandons himself totally in God's hands does not become God's puppet, a boring "yes man"; he does not lose his freedom. Only the person who entrusts himself totally to God finds true freedom, the great, creative immensity of the freedom of good.
The person who turns to God does not become smaller but greater, for through God and with God he becomes great, he becomes divine, he becomes truly himself. The person who puts himself in God's hands does not distance himself from others, withdrawing into his private salvation; on the contrary, it is only then that his heart truly awakens and he becomes a sensitive, hence, benevolent and open person.”