I went to my 30th a few years ago and quite enjoyed it.  Group of best friends kind of structured it differently.  We got together 2 days before and co-rented a big cabin up in the mountains and went and enjoyed time together and lots of laughs.  That group of 10-15 people have all remained close friends even as we've fanned out all over the country/world. 

We had a fun dinner the night before the real reunion, and then this freed up time to speak to people outside that close friend group.  I made an effort to just kind of get around and talk to people, even many who I didn't remember well.  This ended up being really fun.  It was interesting to see what became of peoples' lives, and I can honestly say that all seemed up for catching up a little.  There weren't many drunks, and it was just a good time. 

Subsequently, and on the roughly annual visits back near home, I've made a real effort to reach out and just have a short coffee or visit with many friends (some from other adjacent classes).  This led to not only some nice visits with people I hadn't seen in 30 years or so, but it was just . . . good.  Among that group of school friends, I think I've become a bit legendary for sending out photos with people THEY haven't seen in 20-30 years, and folks seem to appreciate that.   As we've started losing important teachers, there have been some further re-connections.  

Like EEE, I don't remember high school years as the best, but mine were at least filled with some good memories.  It's really life post-college that got the most interesting.  School was a bit stressful especially since I highly prized trying to do well.  This meant giving up a lot of "other stuff."  

Out of all this, I've learned to not be afraid or self-conscious about visiting an old friend or acquaintance.  And I try to steer the conversations to our lives since and some good reminiscences.  No need for global affairs and politics in that kind of meeting.  A few of us have traveled quite a bit so it occasional creeps in as a result of those conversations.  

I think at the end of it all, I really appreciate people.  I'm not down on people.  Even those I don't overtly agree with on many things still have lives and loved ones and experiences to share.  We are more alike than different, and that goes for the whole planet.