When I went to Southeast Asia last year we flew Korean Air for 13 hours to Seoul, followed by a 6 hour flight from Seoul to Singapore. I never fall asleep on airplanes, not even when I take sleep aids. Well, as soon as I boarded that 6 hour flight to Singapore, I fell asleep right there in the seat, before the plane even took off.
I was shaken awake moments later by a flight attendant, because they wanted to make sure I was wearing a seat belt. I was. I never fell back asleep.
My wife had to restrain me from making a scene and shouting about how Takeshima belongs to Japan.