In 1998 I was working at an agency in Portland, Oregon that served homeless teenagers. Also in1998 I made my first trip to London, England. I hadn't told the clients where I was going, and my ability to navigate (plan ahead) in London was poor. One afternoon I was riding in the tubeway. I decided to get off at random to see where I was. The door opened, and standing in front of me waiting to get on was a homeless teenager from Portland Oregon that I'd seen days earlier. A strong double-double take. I got off, she got on, and that's what happened. A pleasant surprise.
This is a kind of "X files" thread.
Post experiences which spooked you, which made you doubt reality, mathematical or physical laws, your sanity, memory or perception. The more improbable the better, but no second-hand legends please, share only what you personally experienced. If you had the event later explained rationally please use rot13 to avoid spoilers.