How do you know so many people?

"So how do you know so many people?" My introvert son asked me this morning. 

"Well, for starters I've been around for 40+ years. I know people," and I started counting them off on my fingers:

These are dear friends we met at uni in the late 80s early 90s.
What a treasure are friendships that last so long.

"from primary school,
high school,
university,
all the different churches I've been a part of since I was a child.
Then there's friends of my parents and friends I met when I got together with your dad.
Then friends I met in Kingaroy..." 

Here he started to get inpatient with me and said,
"Kingaroy, where's Kingaroy? Why Kingaroy?"
"That's where I moved to after I graduated from uni and got my first job."

"But then we became missionaries and it became our job to meet people, going to different churches, and so on. Ever since then it's been one of our jobs to stay in touch with a lot of people. Then we met people in Singapore and in Japan through OMF and other events we've been a part of."

But he was gone, that was way too much information for him.

The original question was sparked by the revelation that I had lunch guests today. Australian colleagues of ours who work in Hokkaido. Our boys have met them a few times, but don't remember them (though I think our eldest did a little).

We do know a lot of people, as I said, it is our job. But my extroverted nature probably contributes (though I know people who have many, many more friends). I love networking!

Of course our jobs/situation at an international school and in an expat community lends itself to a much higher turn over of friends than most monocultural people experience in a whole lifetime.

How many people we know would probably freak some people out, if they knew.