Most recent occasion comes to mind.. I'm a was good in school but now late 20s alright for my local road races but not crazy fast kinda guy. Inconsistent with training but stillngoodnfor 18min 5k, 38min 10k.
Anyway, was in Birmingham for a professional development weekend in the summer and did a morning tempo run along one of the canals. Not going crazy fast, maybe 6:25/mile so going by most other casual joggers v quickly. Then I hear voices coming up behind me, or more specifically a woman chattering away except its catching up to me. Couple seconds later a woman and a dude eases by chatting away like she's jogging. Didn't really get a good look at her face but remembered height, hair colour, clothes etc.
Anyway, I get back to my hotel and go to breakfast and right there in the lobby is the woman now facing me, it was Paula Radcliffe and she was sitting having breakfast with Steve Cram. Turns out it was the Birmingham Diamond League that weekend and those two were the commentary team and I was staying in the meet hotel for the staff.