A friend went to Japan last year and came back with tales of rough treatment on the public transport. ‘Yeah, well you try the London Underground’, was my reply. And I continued to think I was right, until I saw this video. With 80 per cent of the country uninhabited, its 130 million-odd residents are crammed into a handful of major urban centres, making it one of the most densely populated countries in the world. So the lack of tact when encouraging people to fill all empty spaces is hardly surprising.