Even if other people don't practice the good heart, still we should practice the good heart because we want happiness and we don't want suffering. Even if other sentient beings don't practice the good heart or they try to harm us, cause us loss, kill us and so forth, if we practice only the good heart from our own side - if we are kind and only benefit others with our body, speech and mind or at the very least we don't cause harm to other sentient beings, then we will experience happiness.

-- Lama Zopa Rinpoche