Never missed a flight, but my luggage once went to Manchester and I went to London. We were both supposed to go to London. I had just left my finacee in the US (we're married now), I was jet-lagged, and just wanted to go home and be heartbroken, and Monarch Airlines sucked anyway. Either way, I think me blowing my stack at the baggage rep. was not one of my finer moments.
Got my luggage back a week later with a $25 check to apologize. Hmmph.