We are diverse in locale, diverse in hobbies, and similar in temperament. I don't know what keeps a functional family from becoming dysfunctional. Maybe it's in the genes, but I doubt it. I haven't studied this, nor have I read in depth on it. I've pondered, as so many others have, and I've read the psychobabble current in magazines and books. So many theories and so little sense. May I hazard a guess that we will never really know in our lifetimes....