I absolutely agree with all of that Livelovebehappy.
I see it in secondary schools all the time. The nuts and bolts of this teem girl friendship dynamic really haven't changed for decades.
Go back 25 years to me being a teenager and it was exactly the same, excluding one from the group for a while and it Go by around everyone's "turn". Thank God there was no internet back then.
Go back 15 years when I started teaching and the exact same thing was happening, year group after year group.
Then came the internet and chat rooms and it got harder to deal with. Now we have social media and smartphones. The main issue is the same but the bigger problem is that there is no escape from the issues. It follows the girls in school, out of school, day, night, school holidays. No break from it when you're off school. No respite when your phone is confiscated ("fear of missing out" is worse). It's relentless and highly stressful.
Also, the nature of social media means small issues become widely known about, often public knowledge. Involves people you don't know and often, via social media, parents seeing play out it too. One small mistake made when you're in a bad mood gets blown out of all proportion.
I am glad I am not a teenage girl today.