I have read a book on this subject: http://www.amazon.fr/The-How-Happiness-Approach-Getting/dp/0143114956 http://www.amazon.fr/The-How-Happiness-Approach-Gettin

I have read a book on this subject: http://www.amazon.fr/The-How-Happiness-Approach-Getting/dp/0143114956 http://www.amazon.fr/The-How-Happiness-Approach-Getting/dp/0.... The author wrote that happiness was defined at 50% by our genes, 10% by circumstances and 40% by intentional activities. I guess that's a non-negligible proportion we could act on.