Reproach is one of the five strengths that allow us to practice our bodhisattva discipline of helping others throughout our whole life. Reproach here is reproaching your ego. It is revulsion with samsara, or the wheel of painful conditioned existence. Whenever any ego-centered thought occurs, you should think, "It is because of such clinging to ego that I wander in samsara and suffer endless pain. If I try to maintain ego, there can be no happiness. Therefore, I must try to tame ego as much as I can." In this case, you are encouraged to talk to yourself, and to say to your ego: "You have caused me so much trouble. I have no desire at all to hang around with you. This 'you'—who are you anyway?" Talking to yourself, reproaching your ego, in that way is very helpful. You can talk to yourself in the shower. When you are driving, instead of turning on the punk-rock, just turn on your reproach of ego. You can even whisper to yourself when you're with someone else, although you might feel embarrassed. That is the best way to become an eccentric bodhisattva.
Condensed from page 74 in Training the Mind and Cultivating Loving Kindness. Shambhala Classic Edition with foreword by Pema Chödrön.