The time and effort that goes into home life is significant. Of what value is this investment? What is the ongoing benefit of a happy family during childhood?
During our early lives we have formative experiences. Through formative experiences, in a social context, we learn who we are. We then form a blueprint of our own qualities by adopting how other people respond to us socially as our own core beliefs. This blue print prompts assumptions about ourselves, the world and other people. This influences our conscious, moment-by-moment, thinking. Therefore, if people treated me well during formative early experiences I would have positive core beliefs and think good things about myself, the world and other people. Excepting accident and trauma, I would probably be a happy person for the majority of the time. Likewise, if I was treated poorly I would have poor core beliefs. I would probably have bad thoughts about myself, the world and other people and be more prone to being unhappy.
So, a happy family life full of good formative experiences leads a greater likelihood of happiness.