The Dharma is a mirror to show us our faults and accordingly how to correct them. We discover our impurities of body, speech, and mind by looking into the mirror of Dharma. So someone who discovers our faults instructs us as well as a guru. As the gurus and Tibetans say, “Praise is good, but criticism is better,” as criticism shows up our faults, and if we suffer from it we remember Dharma. Praise may kindle pride and make us forget our faults, while criticism teaches us not to commit the same faults again. In the same way happiness is good but suffering is better, because it takes us to the Dharma. Happiness eats the fruit of our past merit.
~ His Holiness the Dalai Lama, The Thirty Seven Practices of the Bodhisattva.
source: Lama Yeshe Wisdom Archive