A new CBS News/New York Times poll - conducted for Sunday Morning - sheds some sunlight on that.
Sixty one per cent of us believe life will be better (for most people) in the future. Back in 1979, just under half of us thought that.
Just one American in eight thinks the nation is more powerful today than it was 10 years ago. In 1979, it was one in five.
Confidence in American-built cars has skidded sharply in the past 30 years. A majority now think foreign cars are better.
A majority of us now think homosexual relations between adults aren't wrong. That's a reversal from 30 years ago.
As for sexual relations before marriage ... the minority who disapprove is growing smaller.
More people now support the legalization of marijuana than did 30 years ago, but still short of a majority.
Views on abortion have hardly changed at all.
Fewer men than 30 years ago think being a male is an advantage. By contrast, more women than before think it is.
Slightly more women want a job outside the home today than did in 1979 ... but it's still an almost even split.
And - this just in - the vast majority of Americans now say they get their news from television. Far fewer rely on newspapers these days. And the Internet is gaining fast.
On the matter of health insurance ... Nearly half of all Americans now want the government to provide it for all problems. That's up from just over a quarter in 1979.
Support for new nuclear power plants has grown since 1979, when memories of the Three Mile Island accident were still fresh.
And - not irrelevantly for a Sunday Morning - our poll finds churchgoing on the rise, with just over a third of Americans saying they attend services at least once a week.