There have been many studies of “the midlife crisis”. A number of research reports have shown that people have different levels of happiness over the course of their lives.
Population-wide surveys show that a person’s average satisfaction with life begins to decline slightly towards the end of our twenties. After that it continues to decline, until it reaches its lowest level during our mid-forties. Then the trend reverses, so that as we pass 50, we are increasingly happy, a situation that is happily not reversed until the last few years of our lives.