What "0" year is connected with their decade the most?

1970: Tbh, the early 70s as a whole felt very connected to the mid-late 60s. The 70s were really just the bad hangover from the 60s (with the 60s being the party).

1980: 1980 was already mostly 80s in my opinion, disco was dead (not to be mistaken with post-disco), synths & drum machines were incorporated in some music, 1980 was already ultra-conservative (the music and fashion really reflects that), the cold war had escalated with the Soviet–Afghan War, the Iran revolution had already happened, arcade video gaming was now huge, Jimmy Carter was already very unpopular and the Reagan Campaign was already gaining a lot of traction well before the election. Honestly, 1980 - 1983 was sorta just its own era.

1990: There was a lot 90s things about 1990 already, it was after the Berlin Wall had fell, Hip Hop had decent popularity, Hair Metal was past its peak, New Jack Swing was popular, House music was also huge too, the Simpsons were a big deal and baggy fashion was already growing in popularity. But, there was a lot of 80s things about 1990, music commonly had primitive synths & gated drums, the New Jack Swing didn't sound very slick (this only applies to early/mid 1990), Hair Metal still had some presence, Alternative Rock wasn't popular yet, 8-bit video gaming dominated, there was also plenty of 80s fashion that bleed into 1990 as well. In my opinion, I think 1990 was mostly 80s until about August (with the Gulf War).

2000: Contrary to belief, 2000 definitely did not feel 90s, I remember thinking 1996 was ancient back in 2000. Pretty much anything from 1990 - early/mid 1997 felt very disconnected, mid/late 1997 - early 1999 felt recent & connected but, with some differences and mid/late 1999 didn't feel different at all. By late 2002/03 though, 2000 was already starting to seem quite out of date. Overall, the 90s and 2000s had a very unique transition.

2010: Despite 2010 having some 2000s culture left over, it was by far a mostly 2010s year. It's sorta similar to 1980 in a way, it was mostly a year of the decade it was in but, only really similar to the other early years of the decade. For example, I would consider 2010 - 2013 as its own era.

Overall, I think 2010 was the most similar year to the decade it's in and it's one of those instances where the decade started exactly on time (in this case, late 2009).

Whoever said 1970 and 1980 don’t understand pop cultural evolution in those decades.

Depends on the area.

1970 in fashion isn't too far out from 1979's, and many 1970 bubblegum, rock and pop hits definitely wouldn't have sounded out of place in the mid-1970s or even later. So I'm going with 1970. Maybe 2010 comes the closest because of some fashion and technology, but its music is so disconnected from the midpoint and the later point of the 2010s that it makes 1970 much more alike with its decade in comparison. 1980, 1990 and 2000 for the most part are all pretty distinct from their respective decade.

They all pale in comparison to 1960 though. Looking back to 1960 in 1969 would have been like looking into an alien dimension.

Apart from the music, not too different really. Late 1983 was very different though atleast.

With 1980 & most of 1983 though, the super conservative politics were pretty similar, the economy wasn't exactly booming in 83 (we were only recovering from the early 80s recession, the economy still sucked for the most part), the materialism of the 80s never really kicked off until 84 (maybe late 83 at the earliest), both years were still in the golden age of arcade video gaming (the video game crash only started in 1983, it's main affect was throughout 1984 actually). Mullets weren't really a thing in 83 yet, the Miami Vice inspired fashion that would be huge in the mid-late 80s was not even a thing yet in 83, the popular TV shows were pretty similar (tbh, this didn't really change that much until 1985) and Type Writers by far dominated work places still. The main differences between 80 and 83 was that Ronald Reagan was actually president (despite already being a popular a figure in 1980), the fashion had some differences (such as teased hair and less 70s leftovers but, it was still mostly the same stuff you would see in 1980), Audio Cassettes were more popular and Cable TV was also a lot more popular too. The music was very different to be fair, New Wave music was bigger, Synth Pop was a lot more popular, MTV was blowing up & Michael Jackson's Thriller was selling like hotcakes (it wasn't 100% different though, Hip Hop had no presence in 1983 yet, Hair Metal didn't truly explode until late 1983, Arena Rock was still huge, Soft Rock such as Christopher Cross was still big). In my opinion, 1983 seems a lot closer to 1980 than 1986.

I'd say 2010, for sure. We already had things like Facebook, HD videos and TV, Windows 7, Barack Obama, hipsters (even if not huge yet), minimalism, Minecraft (albeit only in beta), and smartphones.

I actually don't think 1990 is that far removed from the rest of the 90s either. It already had things like the Game Boy, Sega Genesis, The Simpsons, Disney Renaissance, The Disney Afternoon, Fox Kids, Windows 3.x, DOS gaming. Of course, it did have the Cold War going on and Bush Sr was president, but even then, we were in the fall of communism and it really wasn't like the core 80s Reaganism era either. It also had things like toy-based commercials, NES games, hair metal, and synth-heavy music. it's weirdly connected to both the core 80s and core 90s somehow.

2000 isn't that connected. Politically it's more similar to the core 90s if anything, and whilst many aspects of 2000 such as technology, gaming, movies, and music weren't similar to the core 90s, they also really weren't similar to the core 00s either.

As for 1970, considering The Beatles released an album that year, we can safely cross it off the list.

no 0 year is