Turns out you really can have too much of a good thing—including happiness. Results from a recent analysis suggest that, for most of us, moderate happiness brings the best results in life, says the report’s author, Ed Diener, PhD, a professor of psychology at the University of Illinois.

Diener and colleagues, whose findings were published in the December 2007 issue of Perspectives on Psychological Science looked at the results from a number of studies, including the World Values Survey, which polled over 120,000 people from 96 countries about levels of life satisfaction and personal success. They also considered participants’ behaviors and attitudes. With those scoring10 reporting the most happiness, the results suggest that, for most of us, hovering around 8 is just fine.

“Those scoring 8 do pretty well in terms of achievement,” Diener says. The highest levels of education, income, and political participation were associated with 8s and 9s. And in general, those scoring 7 or above live longer and are healthier, he notes. “But there are some dangers in thinking that you should be a 10. You could wind up always seeking elation and euphoria and higher levels of happiness, and that can backfire.” In fact, 10s tended to make less money and have achieved significantly less educationally than the 8s and 9s.

So what is the key to happiness? Diener recommends focusing on cultivating strong social relationships, having meaningful goals, and nurturing positive attitudes in general.