Funny how you describe yourself as an extrovert and I've always said I'm an introvert - but we identify the same.
Dislikes, anxiety around large groups of (mostly unknown) people, preference for people we know like work colleagues and family.
To your main point, I think it depends on the previous relationship. Most of these folks had months or years to form bonds with coworkers such that I don't think it'll be so easy to reduce them to the concept of a human just from a few months or a year apart.
Consider the hypothesis you have an anxiety disorder, not introversion. I said I was an introvert for years until repeated evidence (and everyone I know pointing out to me) convinced me that I am just happier, healthier, and have more energy if I'm around other people. That doesn't imply that I (or you!) am _good_ at being around other people, especially strangers.
I've taken several personality tests that identify me as an extrovert / leader, and it's true, I tend to lead well as defined by my subordinates over years.
But it's exhausting. Groups larger than a few can only be handled in deep conversation for an hour or two tops. Also I get crippling anxiety before entering certain social situations, especially phone calls to support lines or in foreign countries where the cultural taboos are potentially around every corner.
Leave me with one person though, especially one I know well, and I can talk for hours and hours at full speed.
I have this too. I'm 40 now and over the years I have come to understand it not as anxiety per se. But more as sensitivity. I am extremely sensitive to body language, emotional content, background noises... Details... When I'm in a large group of people there's so much information coming in that it quickly becomes exhausting. If I've slept well and am generally looking after myself I can do large groups for hours at a time. But if I'm tired, it quickly leads to exhaustion which then leads to confusion and anxiety. I also get classified as extrovert in psych tests. And I do love people, it's just they are generally too intense for my poor overly tuned nervous system. I often think I'd do well with a mood stabilizer/anti epileptic.
I believe this is what's considered as a "highly sensitive person". There's some scientific evidence showing that you can identify even babies based on how they react to external stimuli. Basically your brain is hardwired to react more strongly than others - this makes social interactions with strangers quite exhausting, for example. And there is nothing you can do about it - it's just some evolutionary development that occurs in a portion of the population. I recommend looking into it more if you're interested - there is also the book Quiet by Susan Cain.
Yes, this feels very familiar. I find myself energized, outgoing, dynamic, etc around strangers, and then reliving the conversations over and over in my head days later when the energy is gone. I've got one or two great friends who I feel truly comfortable with, and so I have to rely a lot on them for my "extroversion."
After spending a few years being a solo freelancer and then going back to a j-o-b, my wife has commented that I seem more content, happier.
I chalked it up to the stress relief that consistent paychecks can provide, but perhaps I am anxiety-disordered.
Others have mentioned similar traits: being a leader or mentor, doing thing on your own, tackling new projects...y'all have turned on a lightbulb for sure.
Dislikes, anxiety around large groups of (mostly unknown) people, preference for people we know like work colleagues and family.
To your main point, I think it depends on the previous relationship. Most of these folks had months or years to form bonds with coworkers such that I don't think it'll be so easy to reduce them to the concept of a human just from a few months or a year apart.