From the unlikely source of "The Harrad Experiment" (as I remember the line): "The trouble is that when people give love and don't receive love in return, they feel that somehow their supply dwindles."

It is a gift we all hold within us and no matter how often we reach in to grab some to give away, there is, as if by magic, always some which remains. Some would tell you that the remainder is self-love. And it is from the self-love that all of the rest grows.