Over 10 years ago in Brighton, a friend of mine put me in touch with mutual friend of hers to do some music together. She was a singer, and I played and wrote music a lot at the time. So I phoned her, and we talked for ages on the phone, got really excited by mutual interests, made all these half plans, then of course - did not nothing about it.
I also worked at the time for a Swedish company and travelled at strange times to and from Stockholm. About a year after the phone call I was getting a late midweek flight back from Sweden on a nearly empty plane, There were literally 5 people on it, one of whom was a girl sitting just across from me writing in a book. We got talking, I asked to look in the book and saw they were song lyrics she was making up, talked a little more and we both realised we'd talked to each other before! She had decided to go to Stockholm at the last minute on her own, just to have a look for a couple of days.
So we had to do some music, and did a couple of songs together over the next few weeks, then drifted apart. Haven't seen her since, but it's my best small world story.