In my experience, it takes two people, but they're not necessarily playing the same role. Social circles are maintained amongst pretty much any group that has a

In my experience, it takes two people, but they're not necessarily playing the same role. Social circles are maintained amongst pretty much any group that has at least one person who is willing to take the initiative to invite people to things, and at least one person who almost always says "yes" to invitations. I tend to take a relatively Stirnerite view of it: As long as I'm getting more enjoyment out of hanging out with someone than the effort of inviting them, I'll keep inviting them even if they never proactively invite me to do stuff, because it's still in my self-interest. If someone always says "Hell yeah", or at least "Can't do it that day, how about this other day", then the negatives of slight inconvenience of planning are wildly dwarfed by the positive of hanging out with this person I like to hang out with. If they say no frequently, then I'm experiencing far more negatives (beyond the linear scaling of energy to invite per frequency of meetups, rejection is a big demotivator).