You forge friendship through common struggle. You need to offer one another something or you just introduce yourselves and let one another drift off in opposite directions without any bond forged.

You form your first friendships really early on with an extremely strong commonality - the hugeness of the world and your lack of information about it. Literally everything is in common with your peers circa age 2-4 because nothing is established yet. If it weren't for how our society has a habit of breaking these kids up constantly throughout their childhoods I would think those relationships would form the most iron clad friendships you can get if they survive to adulthood. Too bad about 90% of the kids you meet in daycare you never see again after you start school.

School is the next big one, where for most kids they will struggle alongside each other for 13 years straight. The mixing up of classes year to year again hurts the likelihood of strong friendships forming, but you can also just have kids your age in your neighborhood as a strong peer group. You have massive amounts of commonality at that point - you are taking the same classes, you live in the same area, you know the same people, you are subject to the "same" pop culture of your school.

That is where those high school clicks emerge from. The most bonded peer groups of before specialize as they age.

The same hold true into college, but I definitely don't see the same commonality and uniformity there. Going through puberty is really the cutting off point where divergent personalities specialize your interests enough that finding commonality becomes much harder, and you start having much less to offer your peers over their cumulative experiences and engagements.

It only gets worse from there. The more years into life you are, the more interests and specialties you have as a person that makes finding compatibility all that harder. People force themselves into relationships and marriage out of societal pressure. Nobody forces you into friendship nearly as much, so over that hump the lack of compatible people drops to near zero. Its why I think most marriages fail - they are trying to force the highest degree of friendship, when the older you get the harder it is.

Pokemon Go, and video games in general, are extremely effective ways to get people a commonality to force them together and interacting in ways that can build meaningful bonds. A common challenge is essential to bonding. The more passionate you can be about it the more likely it works.

But even then the 30 year old comes with baggage. They already have their favorite movies and musicians. Likes and dislikes. Hobbies and things they want to avoid. Because they have experienced so much more a fraction than they would have as children they are that much more set in stone. The adage of how you can't change a person applies here - even children demonstrate dramatically declining malleability as they gain experience in life. As you gain magnitudes more life experience your flexibility personality wise declines by similar magnitudes. It is trying to fit together puzzle pieces - if the pieces are made of clay you can mold them to fit. If they are tried out and set in stone they are rigid and it is much harder to find a match, and those matches are much easier to fracture and break.

The commonality and struggle are the prongs of a puzzle piece. The more impactful on your life, the happier it makes you, the more passion you can have for it the more pronounced those prongs can be. Early on you only need the simplest commonality as being the same age or living near one another to forge bonds - as you get old and your piece gets more defined and nuanced, it takes larger struggles and stronger forces to bind pieces together.