Tokyo trains are as crowded as crowded gets. To get home at night Tokyo commuters must push their way on and off their train — there's no other way to do it. Constantly apologizing every time you need to do this would be exhausting. People generally skip the pushing apologies. It's just a practical thing.
The key to this polite form of pushing is to:
- Only push out of necessity (getting on and off a packed train).
- Push with your body not your hands.
- Push gently and kindly.
- Make yourself as small as possible to squeeze through the available space (e.g. remove your backpack)
- When exiting the train you can say "orimasu" (getting off!) to give people a heads up.
- If you need to push a group of people unusually hard say "sumimasen" (excuse me).
So next time someone pushes you on a Tokyo train — don't get annoyed. When in Rome ...