Odds are some very specific things popped into your head immediately. To varying extents, and depending on how much you know about history, you will probably be able to come up with similar answers for every decade from the 1920s to the 1980s (maybe earlier too). Probably something like this -- noting that this is not really an accurate description of the decades, just of what has become the iconography of those decades:
- 1920s: Roaring Twenties, flappers, Jazz Age, stock market crash
- 1930s: Great Depression, speakeasies, organized crime, prohibition
- 1940s: New Deal, World War II, swing, USO, film noir
- 1950s: Doo wop, Motown, birth of rock and roll, soda jerks, sock hops, fuzzy skirts, chrome tailfins, excessive optimism, squeaky-clean families
- 1960s: Psychedelia, counterculture, civil rights, hippies, peace movement, protests, maturation of rock music
- 1970s: Disco, shallow materialism, pet rocks, smiley-faces, mood rings, fads, disaster movies
- 1980s: Rampant capitalism, greed, exploitation of resources, selfishness and hedonism, new wave music, MTV
So what was the 1990s about? You'd think by now we'd know, but it seems it isn't really clear yet. A lot of notable things happened in the 1990s, to be sure. The fall of communism and the end of the Cold War, the Internet bubble, ubiquitous computing, and a groundswell of awareness of environmental concerns are amongst the most notable. Somehow this doesn't seem to want to coalesce into any kind of coherent theme, nor does any particular image rise up to claim dominance.
I'm inclined to propose this as the answer: "global awareness". The decade of Ben & Jerry and the World Wide Web; of globalization of markets and of news; the mainstreaming of the environmental, recycling, and conservation movements; the first big steps towards a more global sense of community. Am I being too optimistic? Maybe. But think of this. We don't think of the 1960s as defined by the Vietnam War nearly as much as we think of them as defined by the concomitant peace protests, perhaps because plenty of decades have wars, but the 1960s stand out for having this particular cultural reaction to them (and other things). So while the 1990s were also marked by corruption and petty localized things, those are not defining of the decade nearly so much as the relatively new trend towards a more ubiquitously global perspective.
The decade we're in right now doesn't even have a name. It's usually pretty hard to see from within the decade what it'll turn out to be about, but I fear this particular one is too easy to see: the war on terror, the fall of democracy, the erosion of rights, the undoing of so much of what the 1990s were about. Let's just hope it's someday spoken of as an interregnum rather than a turning point.