Love is the difficult realization that something other than oneself is real. (Iris Murdoch, 20th century Irish author and philosopher)
Parents come to realize very quickly that their young children are very self-aware but seem almost completely unaware that anyone else really exists—except as a resource to provide for their needs and wants. It takes a measure of maturity to realize that others are important, and that realization may not be fully appreciated until you discover love.
Let no debt remain outstanding, except the continuing debt to love one another, for whoever loves others has fulfilled the law (Romans 13:8).