Well when you fill the plane fall like this, you get really scared as it was your last moment.

https://www.youtube.com/watch?v=kIpwuN3cDXY

http://www.nbcdfw.com/news/local/Passengers-Reportedly-Injured-on-AA-Flight-From-Seoul-to-DFW--285971311.html

Ok I just flew our flight back from Sapporo and was on the same OTR1 ahead of AA and it wasn't THAT bad! 

Anytime people fly up and strike their heads on the ceiling along with other loose objects, it is severe.

 

I have flown many times between Narita and Newark and almost always hit some strong turbulence at cruise altitude. It is consistently much stronger than anything I've experienced elsewhere and it has been enough to require that you keep your seatbelt on or else you would come up out of your seat.

 

During one flight in what I believe was a 777, the crew couldn't do meal service the normal way and had to rush down the aisles tossing the food out to everyone as quickly as possible because the food cart would have been too risky to use if the turbulence returned. Everyone was advised to keep a grip on their drinks. I don't mind the feeling of free fall or the bumps, but what was getting me nervous was watching all the components of the cabin such as the overheads and bathroom compartments visibly rocking in their mountings. It seemed like a lot of stress for the aircraft for a period of about an hour.