friendship

This is me and a few of my friends. I have been thinking a lot about friendship lately and i was wondering why we grow apart sometimes?I mean why do we grow apart and lose touch? I hope i never lose touch with my childhood and teen friends. however i know a lot of people do though. And sometimes it's not only your friends you lose touch with but their familes too. i mean If you hang around your friends you can become friends with thier familes too. and when you lose touch you often lose touch woth them too. I want to make a promise to my friends that i will never lose touch with my friends. I want to keep my childhood friends.