The nature of detachment.

Virtue means loving God above everything else. The more you love God, the more you hate evil, and the more you are inclined to avoid it.

However, there's a confusing catch here that the devil often seems to try and get us on to make us detest evil in a way that can actually draw us from loving God; this is most dangerous, because we think that we are being virtuous, and therefore have a difficult time changing our ways. If we love God, we detest evil in ourselves, but evil from outside sources cannot affect us unless God wills it because, since we love God, we see beauty in every soul, and in all of creation and art. Moreover, we are given the strength to not be affected by things that are imperfect. Throughout art and experience, we find that the lover sees nothing but beauty, even if they are surrounded by muck.

This love of God and sensitivity to beauty around us isn't blindness to evil. Rather, it is a perpetual and conscious choice to ignore the devil, because nothing irks the devil more; it also shows our confidence in God to protect us from whatever ends up in our path.

There is one theory that detachment stems from the sensitivity to evil, to the extent that we remove everything that has the least sign of corruption. This theory that we cannot protect ourselves from the corruption around us leads naturally to scrupelosity, which then digresses to a loss of hope in God's goodness and His ability to pull us out from whatever situation we are in. Scrupelosity then causes us to rely on our own powers to overcome evil, which consequently makes detachment pretty much useless. This severe condemnation of everything containing imperfection, on the part of the Puritan and Jansonist movements, has resulted in nihilistic, self-sustaining mentality that currently drives modern society (this is not, of course, to say that we should look for or remain in occasions of sin -- that's a whole different matter).

Detachment, therefore, is not the detestation of everything that has evil in it; nor is it the belief that goodness and beauty is nulled by the presence of imperfection and mankind's fallen nature. We can be overly attached to something that is purely good; this is because being overly attached has nothing to do with the object to which we are attached, but rather to our desire to be in control of our own lives. Detachment means being of this world, but being more interested in things Divine, to the point to where we recognize that we don't need the material world to get to Heaven, yet still recognize and take joy in the fact that the good in persons and things is there for the purpose of leading us to Heaven.
You find that people who are growing in the spiritual life will start to listen to modern music less, watch less TV, read more spiritual books and fewer secular books. Yet they won't necessarily tell you that it is because these things are evil that they are avoided them, but instead because they value God more, and have simply lost interest in things of lesser quality.