Since the mid 1980s, subjective well-being research has blossomed into a major research area in psychology and related disciplines. Subjective well-being researchers have advanced our understanding of the correlates, causes, and consequences of happiness. Some of the early research findings, however, have been overturned lately. The present article revisits the early research questions such as the effect of weather, item order, hedonic adaptation, and money, and summarizes the most definitive findings so far on these issues. In addition, the present article summarizes the recent research on social relationships and perception, which helps explain why social relationships are so important in happiness.