• the economy (in particular the cost of housing)
• how hopeful everyone was for the future
• flash games
• no pandemic

The 2000's weren't great though. Music is music and I don't think there is a golden age of music. There's good stuff today and there is terrible stuff from the past. People treated each other worse in the past. I got kicked out of home as a kid for being gay in 2000, so that sucked. On the upside, housing was cheap enough I was able to pay for rent and living expenses on two minimum wage jobs and finish high school and somehow put myself through college debt-free by taking 9 years for a 4 year degree and working a lot. This is not even remotely possible now. Rent is over 10x what it was then and minimum wage has barely changed. Don't get me started on tuition, racism, homophobia, misogyny, etc. Hate crimes were a big thing at my highschool and no one cared about it.

Technology also wasn't great. We have no much instant information in our pockets now. We can share and view technology and creativity. We can also share hate a lot easier, so that's not great.