The advancements in technology in the 80s and the 90s, especially with the internet, were monumental. The advancements from 2000-2020 are still big, but not as pronounced as the two decades before it.
However, in terms of politics, I'd say 2000-2020 as so much has happened in the past twenty years, and while you have the fall of the Soviet Union and the Iron Curtain in the late 80s-early 90s, the effects of 9/11, the recession, the rise of the Tea Party and Trumpism, etc. cannot be overstated.
My answer is 1980-2000, although it depends on who you ask and what's the most important in their definition of "different."
Pretty much this. I actually voted 2000-2020 because politics both domestically and internationally have changed more radically (outside of the Cold War ending, which was admittedly a pretty huge deal, but between Putin taking over Russia and the rise of China even those basic dynamics haven’t completely gone away). Technology has also changed pretty damn rapidly; you can argue not quite as much as between 1980 and 2000, but then again you can argue it has. I’m wondering if people forget how relatively limited technology was in 2000. Internet was limited, both in terms of what you could do with it and how widely adopted it was. Yeah you could have a Windows 2000 PC with dial-up and AOL, but it was NOTHING compared to today. You could have a Nokia cell phone maybe, but again, NOTHING compared to today.
The most defining moments in our current era I think are:
1. 9/11
2. The creation of Facebook
3. The invention of the iPhone
4. The 2008 recession
5. Rise of populism
6. COVID-19 pandemic
All of that happened between 2000 and 2020. And I would argue together they make the average daily experience of an average person in America at least in 2020 more radically different than they were in most ways compared to the average daily experience of an average American in 2000 vs. 1980. In neither of those years did everyone have supercomputers in their pockets that functioned as phones, cameras, and portals to everyone else on Earth and all the collective knowledge of the human race. REALLY hard to overstate how huge that is.
Maybe the globalization that occurred between 1980 and 2000, which led to a significant decline in poverty in a number of third word countries, was a bigger deal for people in those parts of the world. But from an American/Western perspective at least, I think these past 20 years have had bigger changes.