TL;DR: If you ever wanted to assassinate me, just be a fun and nice person to meet and then invite me somewhere. I will come.
Being socially extraverted, I find myself arranging quite a busy schedule. Going places, talking to people, generally hanging out with people if I get the chance to do so.
My points of contrast are my friends and family. Many of them are more introverted, thus their contrast against me is stronger. I can have a week with 4 scheduled activities (lessons, workouts, etc) on consecutive days, and while it is definitely does physically exhaust me, I don't regret having gone, and done them all . My friends contrast me, as their limited social energy makes them have maybe one, or likely no regularly scheduled activities like that. Likewise, they spend their time at home recharging where I can scurry on from place to place, day to day. And I try to invite my friends to do things with me where applicable. I often plan activities with people in turns, while some are socially recharging, others are ready to go to do something again. Or rather, the fact that people do take their time to recharge leads me to plan activities around that.
This all to establish that my friends like to take things at a slower pace.
That makes it feel all the more meaningful when they invite me in turn to do something. It's not a particularly rare occurrence, they do things and activities too, but often it does skew into me being the primus motor for a bunch of things. There's nothing more delightful than being invited. To do something, to go somewhere, to just meet and socialise, anything, really.
With my friends, I've never needed to be in doubt that they are my friends. The fact that I'm meeting some of them quite seldom doesn't diminish our friendship in my view. And even though I'm often the one to suggest an activity or start a conversation, it is still clear and obvious that they value my friendship too. But being invited back, seeing them start a new conversation over text, it feeds into some subconscious confirmation that releases extra good feels than when I do it myself.
The strength of that feeling is inversely proportional to how frequently each person invites me to do things. And there is also an inverse relationship to be observes in how close friends I am with the person in question, I've noticed. Or rather, that is to be expected - new friendships are more exciting in being new, where old friendships are comfortable in their familiarity.
The absolute kick I felt when a fairly new acquaintance invited me to join them to an event coming up though. That one did assure me of our (to be developed) friendship. Knowing my interactions with this person, I had got along well with them, but I felt that we've stayed in the acquaintance phase. We haven't had the time or opportunity to become actual friends, but I definitely would like to be friends with them. In being left as acquaintances, I didn't expect them to invite me anywhere, rather we'd develop as friends if our paths crossed some other way. But, when they now *did* invite me to this upcoming event, it was revealed to me that I've left a good enough impression on them that they're willing to pursue learning to know each other better.
I was told of a phenomenon in psychology, where, when meeting new people, those people typically like you better than you think they do. I feel like this instance with this acquaintance fits quite well into that phenomenon. I had a good impression of them and they were a very fun person to meet. In hindsight, why wouldn't they have the same impression of me? Perhaps it wasn't as outlandish to think that I'd pass by their mind when thinking of people to ask to join.
I don't know where this acquaintance slots in on the extravert-introvert spectrum, so I cannot enter that data point yet into my observations. But I will find out once we get to the event! It'll be quite the adventure.