same story, good wind, excited

, decide to take small board, drive to beach, rig the sail, get the board ready but the screw is missing on the bl..dy fin, look everywhere in bag, car and else. No one to lend me one (hobart mid week), de-rig, drive home.
I look around no screw. I buy a new one.
Next time, same story, and when I put the fin on... the old screw is sitting there in the board ! It had been there the whole time...