Basically anyone (mostly 1980s and 90s kids but not all of them) who deludes themselves and thinks that the past decades they grew up in were a lot better than the current decade they live in now despite a lot bad stuff still happening in those past decades.
90s kid: I hate today! I miss the late 20th century so much! 80s and 90s forever!
2000s kid: When will you overnostalgic people learn that EVERY decade has bad things happen in them? Were you not old enough to notice the AIDS epidemic, the Lockerbie bombing or the eruption of Mount St. Helens which killed 57 people?
Or how about in the 90s if you were even aware of the Bill Clinton sexual misconduct allegations, the suicide of Kurt Cobain, the Columbine shooting, the Oklahoma city bombing or the rise of teen pregnancy?
90s kid: Yeah, but the music back then was SO much better!
2000s kid: At least I grew up in a time where I was able to access my favorite songs and albums faster thanks to the internet. I swear most of you 80s and 90s kids suffer from a serious case of decade delusion.