Mine would be having decanted my pockets for security – in the days before jackets came off completely. I still made the machine bleep, so was taken over to be felt up. Then my bag was subjected to a random check, and as I was carrying private papers I asked to do this in a private area. Fair enough.
Got home, got to my front door, fished for keys and spotted the problem. It was late, Halloween and I couldn’t rouse any of my friends. After an expensive night in a London hotel, I gave the airline a call and they agreed to put the keys on a flight that day to LCY, so I was able to get home a day later than I expected.