Japanese people take their jobs more seriously than Americans. Here, the job is the focus in life. It isn't just a way to make money, like it is to so many of us. Many people only have friends from work or college. People don't really go out trying to make new friends once they enter the workforce. Some of them will spend 10 hours a day at the office because it is shameful to leave first. I've heard from a guy who works at Sony, that people there will just stay at their desks even if they aren't really doing any work. People will come in on holidays to win points with the boss even though he isn't there. They come in hoping someone will notice and mention it later on.
On the positive side, people seem to take much more pride in their jobs and they become close with those they work with. For this reason, there aren't really low quality places to eat with employees who don't care. Mc Donalds, for example, is full of workers in clean uniforms who are very polite. The place is clean, and the food is decent. I actually eat at Mc Donalds here, but I wouldn't even set foot in one in the US.
It seems that the occasional drinking party with the staff is more or less mandatory. This is where people can let go and drink heavily. They can get things off their chest they wouldn't want to say in the office, such as grudges or romantic feelings. They can make fools of themselves and none of it will matter the next workday. What happens at the drinking party seems to stay there. This is true for teachers too. I've been to a few of these nomikai's (drink gatherings) and they're actually pretty fun. I feel kind of bad, though, for the staff that has family they want to get home to. I've never heard of anyone bringing family or a significant other to any drinking party or school function. It amazes me how they can dedicate so much time to work and keep it seperate from their personal lives.