I lived in a dorm in Tokyo for about four months earlier this year. There were about a dozen students in the dorm, of which I was the only westerner, all the rest were Chinese except for one Burmese guy and one Korean guy, with whom I shared a room.
This Korean guy turned out to be one of the most irritating people I have ever met in my life. He spoke a tiny bit of English and fairly good Japanese whereas my Japanese (at the time) was pretty poor, so communication was difficult. He would use my computer without asking, so after awhile I put a password on it, which solved that problem. He would slam the door every time he came in or out of the room, including in the middle of the night, when I was trying to sleep, which was frequently. The room was only about 4m by 2m with a bunk bed, really small and cramped and my head was by the door when I was in bed, so the slamming was really fucking annoying. He would sing Korean pop songs all the time, really high, balls in a vice style. He smoked and would pace outside the room in fucking slippers which made an incredibly annoying sound, and in between every puff, he would spit, which was fucking disgusting. Every time he spoke he would made this foul sucking noise in between each sentence.
The dorm itself was very dirty, very small and the kitchen was worst of all. The Chinese students would do nothing but cook all day long. They fried everything in about a litre of oil, so there would be oil all over the walls, benches and floors, which was made even worse by the fact that there was no exaust system in the kitchen. And of course, nobody ever washed up. When they ate these mountains of oil soaked food, they did it with their mouths about a millimetre away from the bowl, shovelling it in with chopsticks, making the most repulsive slurping noises. The food itself was really quite gross too. Walking into the kitchen to find a bowl of mouldy chicken's feet is not an experience I want to have to repeat.
End rant.