Appreciate each other...???

It seems like people tend not to appreciate the closest people in their life. Especially those people that appear in their daily life. I kinda find out that sometimes it is much better not to live with your beloved people. The further you are the closer you are. For example, parent with many kids. Some of the kids don't live with them, and some of them do. This parent for sure will think more of those kids who are away. Meanwhile, kids who stay with them will just looks like useful, get the anger from the parent and more to come. Further, if the kids who stay with them decided to move one day, then people will say bad words to the kids. Such as, no longer want the old man, just imagine if they get old one day, what will happen to them, all the curse are coming in. The question is why? What cause this to happen? Human nature? Is there any solution for this? Poor those people...