I think that contrary to popular opinion, friendships don’t become deep because of similarities or differences in personality or interests. Rather, in my experience, close bonds are defined by shared vulnerability. This is common across all of my best friends and strong relationships.
Close bonds can spring from different kinds of shared vulnerability. Most obvious is sharing secrets. But there’s plenty of other kinds:
Maybe you have a coworker you share gossip with. Maybe you find out you both just can’t stand how Joey cracks his knuckles every five seconds. Where’s the shared vulnerability? Both of you have crossed a line (admittedly, a small line), that could create problems for you if it got out.
Experiences can create share vulnerability too. Illegal or illegitimate activities, drugs, even drinking together establish shared vulnerability. Mind-altering substances enhance this effect: lowered inhibitions mean you’re more likely to share secrets and create other vulnerabilities.
Vulnerability can be one-way and still create strong bonds. Consider a typical parent-child relationship. The child has infinite trust for their parent, which stems from the infinite vulnerability they’ve had since birth. No wonder familial relationships are so strong.
Another example of one-way vulnerability are Internet-famous “influencers”. Influencers trade privacy for fame. By leaving their private lives open for all to see, they create artificial, one-way bonds between their fans and themselves.
Does vulnerability beget trust, or does trust beget vulnerability? Perhaps counterintuitively, I think that vulnerability has to come first. After one party takes an initial leap of faith, demonstrating vulnerability, the other party can reciprocate by sharing vulnerability of their own. Once mutual trust has been established, anything that’s less serious is just table stakes.
Shared vulnerability as a model for bonding implies that it’s possible to nudge friendships closer or even create them wholesale. It could be as simple as taking that initial leap of faith with a relatively harmless display of vulnerability!