Adults have an annoying habit of telling young people that childhood was the happiest time of their lives - and enjoining them to take advantage of this fleeting era of well-being. We can forget the heartaches and the thousand natural shocks that childhood and adolescence are heir to - the sheer awfulness of bullying, adolescent relationships, rivalries and acne, and the misery that some can feel at school.
The more realistic among us do recognise the challenges of childhood and the new difficulties faced by today's young. As Sue Palmer puts it in her new book Toxic Childhood: "In a global culture whose citizens are wealthier, healthier and more privileged than ever before, children grow unhappier each year."
So do the grown-ups. A BBC poll found that the proportion saying they are "very happy" has fallen from 52 per cent in 1957 to just 36 per cent today.
There is a growing revival of interest in the idea that adulthood could be made easier if we can find ways of making schooldays genuinely happier - by educating young people to be happy.
Nel Noddings, the influential American educationist, has this to say:
"Happiness and education are, properly, intimately connected. Happiness should be an aim of education,and a good education should contribute significantly to personal and collective happiness."
Everyone is surfing the happiness zeitgeist. David Cameron has announced that promoting happiness will be part of Conservative party policy. He said: "It's time we admitted that there's more to life than money, and it's time we focused not just on GDP but on GWB - General Well-being."
Labour shares the vision. Culture Secretary Tessa Jowell says progressive politics has to make room for "fun, laughter and play".
Both were perhaps influenced by the arguments of such academics as Richard Layard, founder-director of the LSE Centre for Economic Performance, who called for a "happiness-based public policy" in his recent book Happiness: Lessons from a new science.
And so educationists are thinking harder about how to make schools happier places and to educate young people in ways to achieve this most elusive emotion.
One leading independent school has put happiness on the curriculum. Anthony Seldon, new head of Wellington college, says: "Helping to produce happy young adults when they leave the school at 18 is my highest priority as head. I have been saying this for 10 years, but only in the past year have I begun to realise this isn't just an airy-fairy aspiration, but that one can in fact learn happiness in classes."
The Wellington lessons are devised by a former forensic psychologist, Nick Baylis, founder of Cambridge university's Well-being Institute, and are aimed at improving their pupils' chances of leading a fulfilling life. At first there will be one 40-minute lesson per week for pupils aged 14 to 16, teaching the skills of how to manage relationships, physical and mental health, negative emotions and how to achieve one's ambitions. A-level students at the boarding school in Crowthorne, Berkshire, will also attend happiness seminars.
Professor Noddings says one reason she wrote her book Happiness and Education "is to counteract a narrow emphasis on test scores - we have really made schools quite grim places.
"We put such a tremendous emphasis on academic achievement for economic success and children take this to be the meaning of happiness and there is no discussion of all these other wonderful sources of happiness.
"What I'm talking about really is quite a strong intellectual programme that helps kids to understand there are many strong sources of happiness - home is a source, so is love of place, relationships, parenting, character, spirituality and finding congenial work."
But the idea of putting happiness on the curriculum also attracts criticism. Katie Ivens, vice chair of the Campaign for Real Education, says: "The duty of a school is to enable children to achieve. That is the contribution that schools are going to make to the children's happiness as children, and also to happiness in their future lives, and if schools don't focus on this, children will become aimless and lack self respect."
Can we actually teach happiness anyway? Understanding it is challenging enough. It has been a theme of philosophical inquiry for millennia.
As one sage reflected: "The search for happiness is one of the main sources of unhappiness in the world." Most parents when asked what they want from school, say they want their children to be happy. And all around us our culture proclaims short cuts to that end.
Spiritual gurus beguile and neuroscience has found it a subject fit for study. Positive Psychology, a class whose content resembles that of many a self-help book but is grounded in serious psychological research, is now the most popular subject at Harvard university.
The godfather of such studies is American psychologist Martin Seligman, who found that one key to happiness is good friendships. Some London 10-year-olds interviewed recently by the BBC confirmed this, agreeing that they were at their happiest when "with their friends".
They said that schools could help them understand the meaning of happiness - though they could not create it.
However the utilitarian philosopher Jeremy Bentham had ideas about how happiness could be fostered in the young. This is the advice he offered the daughter of a friend:
"Create all the happiness you are able tocreate: remove all the misery you are able to remove. Every day will allow you to add something to the pleasure of others, or to diminish something of their pains. And for every grain of enjoyment you sow in the bosom of another, you shall find harvest in your own bosom;while every sorrow which you pluck from the thoughts and feelings of a fellow creature shall be replaced by beautiful peace and joy in the sanctuary of your soul."