Reading an article written by the Dalai Lama:

This way I have been able to preserve my inner peace. If we are content just to think that compassion, rationality, and patience are good, that is not actually enough to develop these qualities. Difficulties provide the occasion to put them into practice. Who can make such occasions arise? Certainly not our friends, but rather our enemies, for they are the ones who pose the most problems. So that we truly want to progress on the path, we must regard our enemies as our best teachers.

For whoever holds love and compassion in high esteem, the practice of tolerance is essential, and it requires an enemy. We must be grateful to our enemies, then, because they help us best engender a serene mind! Anger and hatred are the real enemies that we must confront and defeat, not the “enemies” who appear from time to time in our lives.