It is considered rude to eat whilst walking down the street, yet no one blinks an eye when men vomit in the street after too much beer.
It is impolite to blow your nose in public, yet small promotional packets of tissues are given away free outside train stations.
It is acceptable for men to urinate in public after leaving the local tavern. I have nothing to compare this with. It's gross.
It is illegal to smoke whilst walking down the street, yet you are never further than 20 metres away from a cigarette vending machine.
It is a common sight to see men reading manga porn on the train, yet you rarely see public displays of affection.
It is a very common sight to see people walking around with white masks over their faces, not to stave off other peoples germs, but to protect others from their germs.
In a city with a population of 20 million, it is quite rare to encounter someone who actually watches where they are going. The norm is to stop in the middle of the footpath, look around blankly, and wait for others to trip over you.
When boarding a train with 300 other people in peak hour, it is habitual for Tokyoites to take only 1 step into the train, then stop and stand in the doorway. This means everyone else has to squeeze past the 'blockers' and prevents anybody from getting off the train in time.
Although everybody has a keitai (mobile phone) and are playing games and texting continuously, you never hear people speaking into their phones, nor are you confronted by annoying ring tones. So polite.