I would call it "Culture Shock", but the Japanese just takes it one step further, and it's known as Paris syndrome. Why? Because many Japanese (mainly women), would go to Paris with this dream vision of romance in the air, and then shattered by rude Parisiens i.e. waiters. So much so, that they go into some sort of psychiatric shock! And the Japanese embassy gets many calls to repatriate the Japanese tourists. Coming from a country that is ultra-polite, it must be strange for them to encoutered rude people, and it must be extreme in the Paris syndrome's case.
London and Hong Kong are cities that I are cities without heart. People just goes about their business. Dublin is going that direction, being cosmopolitan can have these affects, from what I observe and experienced. But would it be enough to cause you mental anguish, breakdown or even suicidal!?!
But are all Parisiens rude? I have been hearing 50-50, and it's just stereotyping them. I think if you go to any other large cities, you will encounter rude people of some sorts. But maybe because I grew up in the west, and encounter all manners of rude people anyway.