I couldn't think of anything worse than a school reunion. Even if I went to an all girl's school
I'm not sure if I take much stock in these "studies" and "statistics", especially with the claim that being lonely is deadlier than smoking 15 smokes a day or whatever it was. A lot of these articles, to me, remind me of the bullshit clickbait that pops up when browsing online.
Speaking from personal experience, I am an introvert who works in a very "people" orientated job. To the point that after the working week is up, I just want to be alone with my books, or my PC games. I have good relationships with people, but there are few (outside of family, and my partner) who I consider to be chummy with, keeping folks at arms length. To the normal person, I suppose that would seem lonely. Does it depress me? Is it killing me? No. I couldn't be happier.
On the flipside of that, I was in a terrible situation many years ago, with my first relationship. We met through Facebook and due to my naivity, I moved in with her shortly after we got "serious". It was the biggest mistake of my life, as I discovered that she clinged to people and had to have them around, people I deemed undesirable and untrustworthy, people that used her and by proxy, used me. (If it helps to add to context, it was a methhead/"Houso" situation). This experience was the worst in my life. I was depressed, it probably did take years from my life.
So overall, I think the mistake these "studies" make is the assumption that all people want/desire clinging to people like shit to a bowl.
