There is a saying that is the underlying principle of tonglen and slogan practice: "Gain and victory to others, loss and defeat to myself." The Tibetan word for pride or arrogance, which is nga-gyal, is literally in English "me-victorious." Me first. Ego. That kind of "me-victorious" attitude is the cause of all suffering.
In essence what this little saying is getting at is that words like victory and defeat are completely interwoven with how we protect ourselves, how we guard our hearts. Our sense of victory just means that we guarded our heart enough so that nothing got through, and we think we won the war. The armor around our soft spot–our wounded heart–is now more fortified, and our world is smaller. Maybe nothing is getting in to scare us for one whole week, but our courage is weakening, and our sense of caring about others is getting completely obscured. Did we really win the war?
–Pema Chodron, from "Start Where You Are"