I'm a wizard, I was a teenager and came into adulthood in the 2000s.
I don't hold any special nostalgia from this period.
I remember the Millenium celebrations which were great, the PS2 that came out in 2000. I watched live 9/11, and thereafter invasion of Afghanistan and Irak (in our school we organized a white protest).
I lived between WE and EE. WE was boring and not really better than now. There was less place to go out, but it was less "multicultural" for sure, safer too. As for EE, it was quite dangerous compared to today, a couple of people got murdered on the streets of my neighborhood, corruption was galloping and everywhere, poor outdated infrastructures, big criminal groups made the news. Today, it's so safe, it's almost boring, no visible organized crime nor violence (it's far safer than most places in WE), ordinary corruption brought to WE levels, construction work everywhere. But, being recently in WE, I still prefer our "monoethnic" country, even with all its default. I really felt homesick.
As for social media, it was much less than today but already existed. Facebook was popular in 2006-7 amongst my classmates, there were plans for Edge-3G beginning this date. Communication by SMS and MMS was the norm, but also the light internet on camera phones, and email. Remember Kazaa/LimeWire? Even before in the late 1990s-early 2000s chat groups were popular, and people were chatting with strangers, much-closed chat groups existed and were easy to create. My classmates had often discussions between them. Internet was slow - 56 KBS phone modem, in 2002 ADSL 600 KBS, next year double. Not yet 4G. HD cameras began to be used in the mid-2000s, and digital camera outran old 135mm film camera. PCs were slower. Smartphones era began in 2008. Online dating was popular. There were less low-cost airline destinations than today.
Other than that, the only positive I could see, the lack of Tinder and like apps, which was much cooler. But, if I was a teenager/adult I would definitely prefer the 1990's and all the changes in Europe during that decade. As you see, for me it wasn't any better. I like EE more, which I find better today than in the 2000s. Let WE rot in hell, it's too late to recover. I only beg my country to never become similar to WE and make the same mistakes as WE did.