An alternative explanation can be the experiences that one has in his or her life. Depending on the experiences that one goes through, whether such experiences are problematic or joyous (and not limited to just encounters with people), one may be more capable of or prepared for tackling potential problems that appear down the road towards achieving a higher well-being in life.
I strongly agree that the experiences one has during their life plays a large factor in one's overall well-being, especially childhood experiences. What one experiences as a child usually has a strong effect in later life since those experiences (or memories of those experiences) are the foundation in how a person may deal with certain situations and thus affecting overall well-being. For example, certain experiences of fear (e.g. being bitten by a dog, falling off something high) as a child can lead to phobias later in life. Thus, these kinds of factors play a role in a person's well-being. To simply put it, the more "positive" or "happy" experiences one has a child, the higher his/her well-being will be.
