"Kindness is the act or the state of being kind, being marked by good and charitable behavior, pleasant disposition, and concern for others. It is known as a virtue, and recognized as a value in many cultures and religions (see ethics in religion). Research has shown that acts of kindness does not only benefit receivers of the kind act, but also the giver, as a result of the release of neurotransmitters responsible for feelings of contentment and relaxation when such acts are committed. "
http://en.wikipedia.org/wiki/Kindness