Some time ago in a different place and a different time, a young warrior student came to his Sifu with anger toward a person who had done him wrong.
Sifu said to the young student; "Let me tell you a story... I too, at times, have felt great hate for those that have taken so much, with no sorrow for what they do; however hate wears you down, and does not hurt your enemy. It is like taking poison and wishing your enemy would die. I have struggled with these feelings many times... it is as if there are two tigers inside of me. One is good and does no harm, it brings joy, peace, love, hope, sharing, serenity, humility, kindness, benevolence, friendship, empathy, generosity, truth, compassion and faith; he will only fight when it's right to do so and in the right way. While the other tiger only knows fear, anger, envy, sorrow, regret, greed, arrogance, self-pity, guilt, resentment, inferiority, lies, false pride, superiority and ego. The littlest thing will make him angry, He fights everyone, every time, for no significant reason, he cannot think. This same fight is going on inside of you and inside every person."
The young student kept silent for a minute, and then asked, "Which tiger will win Sifu?" Sifu replied; "the stronger one."
"Which tiger is stronger?" he asked again”,
... The one you constantly feed..."
Author unknown