Where there is sunshine, there is shadow.
Where there is beauty, there is ugliness.
Where there is virtue, there is vice.
Where there is humanity, there is meanness.
The world is imperfect. However, because there exist shadow, ugliness, vice and meanness, we can appreciate sunshine, beauty, virtue and humanity better.
It is arranged by God. As Benjamin Franklin ever said, “God will certainly reward virtue and punish vice, either here or hereafter.”