An excerpt from a 2002 research report authored by Ed Diener and Martin Seligman – two of the fathers of modern happiness research – titled “Very Happy People“:
The very happy people [from a sample of 222 undergraduates] were highly social, and had stronger romantic and other social relationships than less happy groups…. Compared with the less happy groups, the happiest respondents did not exercise significantly more, participate in religious activities significantly more, or experience more objectively defined good events. No variable was sufficient for happiness, but good social relations were necessary.
(Emphasis added.)