Endless love or dissapointment?!

At least one thing but a very holy thing – the feeling of being a mother and care your baby and love it endlessly- unites all female beings in the world. However, still there is a difference distinguishing human mothers from non-human ones more or less. I will come back to this difference at the end of the essay after talking to you a story which will give me a better opportunity to express my thoughts.
The story, which is called “the legend of a swan” is about a mother who felt happiest and proud for having three sons and did her best to see them happy. Once, this mother fell ill. The bed-ridden mother felt so fatigue that she couldn't get up the bed to quench her raging thirst. Just then seeing her eldest son coming home the sick mother asked her beloved son a glass of water but the boy didn't give, because there were his friends waiting for him outside. The poor mother saw the same neglect from the other two sons as well when she asked them for water. At that moment the only thing that she wanted was to be a swan so she could fly and drink water till she quenched. Here it is, God granted her wish, so she became a swan, left her home, flew and flew as far as she could, and perching on a coast of a lake she drank water till she slaked. And since then she lived in other birds' nests and never hatched.
For me, this is more than a legend, with its very real problems- endless parent love, negligence on the part of children and a deep disappointment.
Thus, parents love their children, take care, and protect them till the end. Maybe it is this endless love which hurts them so much when they see coldness from their children. Parents think children as a part of them, it is true but till children are born, birth is the first step separating mother and her baby. When children do not place into your arms, they get farther from you, then this getting apart is followed with each year added to children's age. Finally, they become independent persons with their own problems, thoughts, dreams and ambitions, but not a part of their parents any more.
Here is the difference that I promised in the beginning-as humans, animals do love and care their babies as well, but unlike people they do it till the time they raise their babies for the independent life and maybe just because of that they do not take offence the unfair life. I really ponder, if it means they understand life better than us?