If you start helping others without any expectation, you are making others to smile happily. In this case, you are building your network and the image building increases.
If we start help others voluntarily, who knows, some time in the future he can help you in a different way or someone can help you voluntarily like you.
In Toronto, the climate is around -16 C with worst windchill, am with my pregnant wife and aged Mom went to Sai Bajan from our home. We went in Public Transit and reached the Bajan Center around 6:20 PM and not able to walk 500 meters . Somehow, we reached the Center and attended Bajan. The Volunteers of Sai organisation helped us to drop while we are back. They voluntarily helped us and it made my whole family in to joy. If some one comes voluntarily and offering to help in critical situation, it will make us very happy and joy.