In Japan, it’s frowned upon to sleep till late, and perceived conscientious to work or study long into the night. The Japanese like to boast that they fill their time productively and, therefore, sleep is synonym of laziness. However, in contrast, doing "inemuri" (don't call it "nap") on the train or at the office is acceptable: Needing a quick inemuri proves how hard you work. It is seen as positive that somebody falls asleep in your meeting because it shows that, despite being exhausted, they still committed to attend.