Scientists say they can measure happiness, and they claim it can make us more resilient and creative, harder working, healthier and even live longer.
So shouldn't the government intervene and make us do what's good for us or at least encourage us?
We journey to the Himalayan kingdom of Bhutan, which is the only country in the world that puts happiness at the heart of government.
A new form of psychology - positive psychology - suggests we can think ourselves happy and actually rewire our brains to be more optimistic.
We are told we all have a set range of happiness. Now positive psychologists say we can make ourselves 10-15% happier permanently - if we work at it.
And they are keen to try it out on a whole nation.
As a society we are richer than we have ever been but according to scientists we are not any happier.
Psychologists say we are driven by our in-built need to compare ourselves with others, and we quickly adapt to money and possessions.
We explore what could be done to improve our consumer society - should we ban advertising for children, tax the rich, commute less or work less?
Scientists say happiness makes us healthier.
Happiness seems to have a protective effect, giving us some protection against heart disease and cancer.
The science of happiness has persuaded influential figures in government to consider ideas which could lead to a complete rethink in the NHS.
Trust, community and friendships are crucial to our happiness and health. But trust has declined dramatically since the 1950s.
Research suggests that a decline in agreed rules of behaviour, commuting, and even the TV are partly to blame.
The science of happiness poses questions about multiculturalism and whether we should do much more build bridges between different communities.
Technology promises happiness at the flick of a switch.
But labour saving devices and technological advances have not produced lasting happiness, and we have all ended up working more to pay for the latest gadgets.
We are told we should teach children to be happy. They have started teaching happiness in the USA and now happiness is entering the classroom in the UK.