Where did you make most of your friends after high school /college?
Rock climbing. Partners are almost a must. Also, finding pot led to connections. These were mostly the same people. Best I've ever known and I miss them sometimes.
After High School, I was a Sound Man for bands. My friends were, for a long time, the musicians in the bands I worked with. I have meet some people through MeetUp. There was also some Yahoo groups. And before the Internet, there was a social group from Leisure Learning Unlimited.
Clubs, clubs, clubs, used to be work, best standing... the US Navy. Now retired... clubs.
Really didn't have but 1 or 2 at a time, mostly co-workers, changed jobs a lot and I'm an introvert.
Work, Work, and Work and local pagan covens and events....and then MySpace...then Facebook....
The US Navy and at the various schools I’ve worked at since I retired.