I think there've been a few, some not particularly significant, but two spring to mind. The first was October 1973, and just about to leave for the flight back to the UK from Germany, having completed a large NATO exercise. Then the second Israeli war kicked off, someone hit the 'Oh Sh*t' button, and we were turfed off the transport and put on stand by.
The second was one particular night in December 1988. I was driving back to Cheshire, after a business trip to Glasgow. It was dark, cold, and damp, and I'd decided to get on my way a little earlier. After about forty five minutes of driving, a sudden bright glow appered in my rear view mirror, just over the crest of the hill, about five or six miles behind me.
An hour later, maybe less, the car radio announced the crash of an aircraft at Lockerbie.