Have you ever seen pictures of trains in Japan during rush hour where people are being paid to stuff even more people into the already more than fully packed trains?
Now imagine yourself leaving Tokyo for the weekend with a little backpack on your back (where else ;-)) and a little trolley squeezed in front of you having to use one of those trains. I can tell you it is fairly uncomfortable! For the whole time of the ride you feel like falling over your trolley - except that you cannot really do that as there are too many people behind and in front of you; and yet you feel on the one hand the strong urge to fall but on the other hand also to keep yourself physically from doing exactly that; you can imagine that you end up with relatively tense muscles.
As I knew this having already had a "painful" experience in one of those trains - when going to the airport -, my mood elevator dropped significantly the second I saw the train coming and being so packed. The second I entered the train, I felt a rush of aggressiveness. I was so angry at all these stupid people around me, just because they were there - everywhere - and made life sometimes so much more unpleasant.
But guess what happened next?! I felt the amazing quietness, I almost have to call it relaxedness, of the Japanese people around me, accepting their fate of having to live with all these other people and having to use these shockingly crowded trains.
And I immediately became a lot more relaxed!