Karoshi is basically when you drop dead after working really hard. It's really common in Japan, but also in American high schools. People in Japan have been known to have strokes, heart attacks, and even brain aneurysm's from working so hard. Some of these workers weren't even paid any overtime. Some were working 12 hours a day. This is unheard of in polite society. Japan finally placed a limit on how much work is too much after World War II. It was also common for business executives to drop like flies from all the stress and "work" that they performed (Golfing really gets to a man).