what about the father's father? did he not show love to his son? and what about the 45year old man's son? did the 45 year old man not show love to his son?
when you do something for your children, do it because you must, because God has chosen them to come through you. Dont maintain a database of what you did for them, and expect glorious returns in your old age. that is the height of selfishness. you brought them in this world, they didnt ask you to bring them.
the love for children passes from generation to generation. what my father did for me, his father did for him, and i will do for my son. no one is doing anyone a favor to anyone. yes children have a socially chartered duty, but that is not the law of nature, so it is weaker. even animals care for their kids, but they dont go around henpecking for returns when they grow old. are we worse than animals?