Helpful Enemies
As Shantideva says, there are many beings to whom one can make charity, but there are very few beings with respect to whom one can practice patience, and what is more rare is more valuable. An enemy is really most kind. Through cultivating patience one's power of merit increases, and the practice of patience can only be done in dependence upon an enemy. For this reason, enemies are the main instigators of the increase of meritorious power. An enemy is not someone who prevents the practice of religion but someone who helps practice.
-The Dalai Lama, The Meaning of Life from a Buddhist Perspective
