I flew back to the States from South Afriza on either KLM or Air France in the mid nineties. I had been on the road for two months in Asia and Africa, and I was exhausted. On the leg from Joburg to either CDG or AMS, I was downgraded to coach (full flight, not a member of the FF club, cheaper ticket, airline worker strike, I forget what the reason was).
Anyway, I just wanted to get home at that point, so I said whatever and took the boarding pass and boarded the plane. Massive mistake. My seat was in the last row of the front coach section, in the middle section, in the middle seat. On either side of me were two hugely fat Frenchmen who had failed to bathe during their time in Africa, but had found the time to drink enormous quantities of alcohol. My disgust at the idea of the first guy sitting down next to me turned to horror when the second guy sat down on the other side.
We took off, and they both fell asleep instantly, snoring and breathing wine fumes grossly from their open mouths, slobbering at times onto their own shoulders. That was my personal nightmare flight, and I have had some odd ones. No sleep, in coach, crushed and farted on and breathed on, unable to get out to the bathroom, nauseated, and forced to look at a clock on the wall that counted down the hours to our destination.
Only because I was young and studly did I survive that one. On the bright side, I can compare most other "bad" flights or unfortunate circumstances to this experience and say, "Well, it could be worse."