For example, the alcohol, as brought into spotlight by 'Animats. It's rather well-known (if a little tough to admit for many people) that alcohol is the "social lubricant". The way it lowers inhibitions and "screens off" pent-up stress, helps people make connections, build and nurture friendships.

It's not the only way to do this, but it's a way that works, and scales well among and across social strata - a fact that's been recognized since time immemorial, and the millennia of culture built around drinking only reinforce its bonding effects.

Serious iron gyms are usually a lot more chatty than commercial / for everyone gyms.

None of them are like the pub though, the pub has no activity other than socialising, it's the entire point.