Why is happiness so important anyway?

I have just completed my MSc in Applied Positive Psychology (MAPP) at the University of East London and have been left asking this question.  People nowadays seem obsessed with finding happiness and constantly feeling happy yet this isn't realistic or very productive.  Happiness surely is an emotion that comes and goes and the low times make us appreciate the high times better.  My passion for positive psychology wasn't about finding out how we can make people happier as the ultimate goal, but that I understood that many of the techniques and interventions in positive psychology could enable people to achieve more, to flourish, and the by-product of that is that they become happier.  My research looked at positive psychology interventions that enabled adolescents to develop a mindset that would promote academic achievement. 

My study focused on children from Knowsley and research conducted by Ofsted and the Department for Education in 2009 surprisingly found that teenagers from Knowsley were in fact the happiest teenagers in England.  This being the case it makes me wonder why Knowsley remains bottom of the league table sitting nearly 20% below the national average for children achieveing 5 A*-C grades.  Happiness research suggests the happier you are the more you succeed and that happiness leads to success but this isn't the case here so what is going wrong in Knowsley?  Research conducted by Oshi, S. et al.(2009) found that high levels of happiness correlated to successful close relationships but it was in fact people who were less happy who achieve and succeed in key areas of their life including education, political involvement and earnings. 

Therefore if we look at happiness on a 5 point scale sitting around 3.5 is the optimal level of happiness for achievement.  It seems individuals who are too happy may be overly content with their life, even if their circumstances are less than perfect and the lack of negative emotion stops them from acting and making changes to improve the quality of their life overall.  Therefore pushing people to constantly feel happier is not necessarily a good thing.  Feeling low often enables us to re-evaluate out lives and motivates us to make the necessary changes to make our lives better.  Maybe the key for Knowsley is to make their children less happy?