From a millenial standpoint, the 90's were great because:
-Most people didn't feel like they were being spied on (either by government or some rando with a phone camera like today)
-Things had a set schedule. Your favorite show came on TV at a certain time and if you missed it, too bad oh well. Now it can be watched any time, and even though that's nice, it doesn't make the experience feel special.
-Movies were being worked on by people who actually lived quite a bit of their life. Now it's mostly being done by fresh art school graduates who do crap work for crap pay because the industry went for quantity over quality.
-Music scene was alive. Lot of experimentation was going on, new genres of rock, hip hop, techno, you name it. There was something brewing in every corner for every demographic.
-People had problems but they were also much more competent because you had to be. Example: Driving to a town you've never been to before? Get a physical map and write down directions, memorize them and follow those during your drive. Even day to day tasks took more effort, and that made people more resilient. It was also the last point in time where you would pick up the phone without having a clue who was calling you.
-People were less scared of everything. Might have been because you only got so much information from the daily news, but I remember the only kind of news most paid attention to was the local news because that was the only thing that affected them that they could do something about. World events would get talked about too, but unless it was a huge scandal or event, it wasn't worth worrying over. Ignorance is bliss.
As for the negatives, all I can think of are:
-Start of mass-prescribed pharmaceuticals. A ton of kids were put on Ritalin, teenagers were given Prosac and it looks like adults were trying to clean up their act after the crack/cocaine 80's epidemic because street drug usage was low in the 90's. Then the 2000's came along and all of a sudden, 'pain reliever' usage tripled because everyone got into the system of being medicated. Meth was also a major problem in the 90's, as was ecstacy. No way those issues just came out of nowhere.
-Children were marketed to WAY too much and adults went overboard with 'think of the children'. 90's kids got not just one, but several TV channels just for them, every fast food place had a playground, Walmart and Target started competing with Toys R Us in the toy market share and exploded in profits, things like that. As a result, Millenials became similar to Boomers in that we grew up in a culture that was focused on us and did too much to make us happy. Millenials are now mindlessly consuming and buying unnecessary things for a dopamine hit because of it. I don't watch that many ads, but most ads that I do see are STILL specifically catering to Millenials because we just can't stop playing with toys. No wonder Millenials and Boomers butt heads so much, Gen X got their asses kicked by boomer parents and had to grow up fast and zoomers weren't taught shit and left to their own devices. And no one even talks about about Gen Alpha.
-It was kinda boring. In a way that's good because things were more simple, but idk it sort of just felt like society was dealing with the hangover from the rager that was the 80's. Might have had something to do with the Cold War ending and attention was then focused on problems at home. I'm guessing that's what it was because the war on drugs was top priority from what I remember.
TLDR: It felt relatively peaceful, but a lot of ominous things kicked off there. It was the calm before the storm that the Internet brought to the public.