First, I have to say that I found much in the earlier seasons relatable...though Sunnydale High wasn't like any public school I'd gone to, from its dress codes to its gothic library. (Principal Flutie was a popular school stereotype at the time but I never encountered anyone like him, unless I want to count a passive aggressive school counselor who was deliberately malicious.) I should also add that I only did 2 years in high school (and didn't do the full year of either one before I left), one year in a special program for delinquents (and thus separated from the general school population), and have never gone to any school dance in my life, let alone prom. I am NOT nostalgic for those days, and the very thought of my waking up a kid again makes me shudder. And yet seasons 1 to 3 still work for me.
Likewise, I never went to college, nor did I join the military. Offhand, that's about all I remember of the mundane aspects of season 4. I still like the season, though. As for what was most relatable...all I can think of is that I've had to help care for people withdrawing from drugs and/or alcohol as Buffy did Riley, and that's it.
I guess it's just that I love scifi, fantasy, and even (dark) faerie tales, always have, and that's what draws me to the stories of the show.
Also of interest (to me anyway), season 6 is arguably the one I could relate to the most, as I was living very poor at the time I saw it and had to deal with stalkers, drug addicts (hell, I helped prepare and sell drugs when I was a kid on the street), been locked in a mental hospital as a kid where an evil doctor tried to distort my sense of reality, and back then I also dealt with death (such as the horrid death of my best friend), loss, and violence of all sorts. And yet it's the season I dislike the most.
Perhaps because it's written in a way I find a penny dreadful of what people who never experienced such things imagine it to be like, or maybe it's because it deliberately stepped away from metaphor that I loved so much and tried to make it a bit more realistic (failing in the process, IMO, though I'm aware others disagree). And even for angst and realism, I'd say season 5 did that better, and season 2 actually ended on angst, unlike season 6.
Good gods, all the funerals I went to and graves I visited recently....I wonder if I dare watch season 5 again soon....😱