All happy families are alike, each unhappy family is unhappy in its own way, "that's how Tolstoy's book begins, Anna Karenina
Each of us has his own idea of happy families. Basically they are the same (mutual support, understanding, respect, etc.), but mostly it is, but still, happy families are much different than each other. These differences can be in material prosperity, habits, relations between spouses and children, entertainment, order, even residence! Both rich and poor families can be happy and unhappy.
At the same time, it is impossible to identify the causes of the unhappiness of all unhappy families, since the causes of unhappiness are always different.