Been thru Narita 2 times and Haneda airport once (round trip), one time thru Taipei. Always coach. On the flights themselves never had turbulence. I don’t sleep either. I usually drink thru the flight (as much as possible) and listen to music or watch in flight movies. Not too bad considering the time. Flew Japan Airlines and China airlines and liked the friendlier service and food better, but had good experience on United as well. About ever time I went thru narita there is a long layover, I try not to buy any crap or eat in them, so plan accordingly. I don’t really smoke like that now, but all Asian airports I been thru have smoking rooms, some dispense beer in vending machines. Occasionally I’d fly with a can of tobacco. Also, don’t forget the 311 liquids rule