I think I can guess the answer to this, but I've often wondered: are the ridiculous amounts of hours worked by salarymen genuinely due to the amount of work to be done, or is it a "face" thing, e.g. "if I'm the first one to leave, I'll look like I'm not committed to the company" which results in longer hours for everyone?
AFAICT, it leans more towards face saving, altho not exactly that. If you leave before the little boss who leaves after the big boss, then your coworkers tend to think you're not dedicated (hrs-in = dedication). However, most people 'working' after 6 are not really working, or at least not productively. Lots of the people who are not IMing or chatting or surfing or whatnot are doing things manually (like running reports) which could have easily been automated --but the boss likes people to 'do work'... efficiency is sometimes seen with suspicion.
That's anecdotal and not necessarily representative, but it certainly indicates that not all people are busy till 11. There's also having to go out with the boss and colleagues.
