This refers to when two or more people encounter each other in completely coincidental fashion. You might notice your old classmate from three countries away is now your waiter in a place you had no reason to expect them in, and you might say "wow, what a small world". You might notice two people who you know from completely different spheres miraculously know each other. You might recognize by chance that your penpal has made a cameo at a venue you're at.
But what was your most profoundly coincidental encounter?
Well, people have always said that is the type of person to get into politics.
(they are, in fact, two separate people. He became a youth pastor. I also remember he stopped bullying me in year 3 when he found out I could draw dinosaurs pretty well)