2000
The last full year of the roaring 90's, even though some wise ass might point out that it's not literally in the 90's. It was the 90's generation still.

2000 was a year of hope and naive hope for the world to keep going the way it was.

And so it was, until, BOOM, 9/11 happens, we go until a war, the economy crumbles, there's mass shootings, kids become socially fucked up, and the world sucks.

I think all 90's kids will remember 2000 as the last year they can look back on and think "damn, what a time to be alive" It really was. 2000 was a time to be alive. We all naively hoped that the prosperity of the 90's would go on forever. But indeed they didn't, and the Roaring 20's should have taught us that prosperous generations usually come to a very abrupt end with no warning whatsoever. If we're ever lucky enough to live in a prosperous generation like that, just remember, enjoy it while it lasts, because it WILL end abruptly. We've learned that the hard way twice. First in 1929 and then in 2001.
2000 really was a time to be alive. Everyone had a good will, no one was scared, and teenagers weren't so damn dysfunctional and arrogant.