"Don't worry, be happy," sang Bobby McFerrin more than 20 years ago, and entire industries geared towards promoting social and emotional well-being in all walks of life have been taking him at his word ever since.
But it is not just adults who are eager to find ways of approaching life in a more positive way; the art of happiness is increasingly finding its way into nations' classrooms as well.
For example, the Willy-Hellpach vocational school in Heidelberg, which can justly claim to be the vanguard of the "happiness lessons" movement in Germany. It all started three years ago after a nationwide survey revealed that pupils were of the opinion that "the only thing worse than school life was having to go to the dentist".
This galvanised the school's enterprising headteacher Ernst Fritz-Schubert into devising lessons, together with a team of experts, aimed at improving pupils' capacity for enjoying life, coping with problems and developing their personality.
Mr Fritz-Schubert concedes that "there are a lot of ways of doing this". In Britain, it was Wellington College that led the way when the school introduced a programme of well-being for its 14 to 16-year-old pupils some four years ago to help them cope better with problems of adolescence.
At Wellington, RE teachers received special training in "positive psychology" under the aegis of the Well-Being Institute of Cambridge University and classes were held once a fortnight.
At the Willy-Helpach school, by contrast, happiness lessons are an official subject on the state-wide curriculum that pupils can opt to study for the Abitur (German higher school leaving certificate).
Mr Fritz-Schubert's methods, based on the principle of personal experience and hands-on projects, include role-play, exercises in concentration and self-awareness as well as sport and music, to boost pupils' self-confidence and encourage them to assume more responsibility for their own lives.
Schoolgirl Jenny, for instance, remembers one session where pupils had to let themselves fall backwards into the arms of fellow pupils. She admits this was "very difficult" for her, as she wasn't sure whether her classmates would do it properly. When all went well, however, she realised what a nice experience it was to be "supported by others".
Meanwhile, Mr Fritz-Schubert has published a book charting his experiences, from the initial idea to the reality of integrating the concept of happiness into school lessons. He hopes to encourage young people to talk about their aims in life, recognise their strengths and weaknesses and see their emotions as valuable resources. That way, he feels, they will acquire the skills necessary to make a success of their lives.
The idea is catching on. About 30 schools throughout Germany are trying "happiness" lessons, while several schools in neighbouring Austria are running pilot projects to introduce the concept as a school subject.
And how have pupils benefited? "The course made me more alert," said one girl, who added that she feels more alive and lives life more "intensively" as a result of the classes. Mr McFerrin would approve.