That is called "letting your light shine before men, so that they may glorify God". As Christians, we are called to be examples. But, since we are human, we are imperfect. Jesus himself was perfect and sinless. He is the example that all Christians strive to emulate. But we all fail. All of us. But, we never stop trying. But being an example doesn't mean that we should not try to make the world a better place. But, that should be driven by compassion and obedience to God, not by personal gain. You will not find a perfect Christian. Some exhibit Christ-like character better than others. The failings of humans do not negate Jesus himself. And God knows that we are not perfect. And he loves us anyway.