I'm always randomly meeting people in unexpected places, to the point where it no longer surprises me. Some examples:
1. Once I was meeting my dad for dinner, and was waiting for him outside his office around 6-ish in the evening. A guy walks out of the elevator, I stare at him, he stares at me, our mutual recognition hits at the exact same moment. He was an acquaintance from university, who'd just started working for my dad's department that week. Oh, and his job had absolutely nothing to do with what he studied at university, he basically just took a chance with the job application and got the job. And his boss just happened to be my dad.
2. Back in my undergrad days, a bunch of us decided to go on a three-day trip snorkeling on an island off the coast of Taiwan. My grandparents decided this would be a good time for them to join a tour group and spend a week or so journeying around Taiwan too. At the end of my three-day trip, I was at Taidong Train Station, basically a tiny train station in the middle of nowhere, sitting there waiting for my train, when a tour bus pulls up. The door opens, and my grandparents emerge. Quite coincidentally, their arrival in Taidong coincided with my departure. I ran up to them, greeted them, and almost gave them both heart attacks.
3. Bit of an indirect one here. Once, my then-girlfriend-now-wife and I were browsing a shop in a department store. We split up to browse the stuff that would interest us. I finished my browsing and went looking for my girlfriend, and I accidentally bumped into a very petite young woman, knocking her into a shelf. I helped her up, apologized, and we went our separate ways. I found my girlfriend, and she said, "Hey, I think I saw a girl I knew back in junior high. I haven't seen her in years! Lemme go find her." We find her, and lo and behold, it's the girl I knocked down earlier. It was awkward, "Hey, your boyfriend almost killed me a few minutes ago." Anyway, this gave them the chance to reconnect, and the friend later served as a bridesmaid at our wedding, all because I ran her over in a shop, completely by chance.
4. Personal favorite here. Due to my dad's job, we moved around the world quite a bit, following where ever he was posted to. As a result, not only was it hard for me to make friends (because I'd just have to leave them in a few years and familiarize myself with a new group of people at a new place), it eventually made it hard for me to remember faces, because I'd see so many. In 1997, he received his orders to move from Washington DC to London. Before we moved, we had a farewell barbecue with some friends and coworkers, at which I met a girl who'd moved there only a few days ago. She and I kind of hit it off, but I eventually ruined it by starting a massive water fight, and her Tamgotchi got soaked, ruining it. We moved away a few days later, but I always felt a bit bad about breaking a little girl's electronic pet.
Fast forward fifteen years. I'm now studying English literature at a university in Taiwan. We get a transfer student in our department, and she impresses me with her accurate English pronunciation. I get her MSN address, add her, and we start chatting that evening. She tells me her dad was posted to Washington DC for a few years, which is where she picked up her English. I asked her when she was there, and we calculated that there probably wasn't any overlap, so we probably never met each other while we were there. I asked her if she liked her time in DC, and she said it was really hard to make friends at first, because she didn't know anybody, and she didn't speak the language, and even the Taiwanese youths would pick on her. Why, there was this one asshole at a barbecue, who poured water over her and destroyed her Tamagotchi.
I was all like, "No... freaking... way..."