Strange as it may seem, politeness is not universal. International standards of courtesy vary considerably. Total immersion courses in the UK, or another English speaking country help students overcome not only differences in language, but also cultural differences.
In Britain, it is usual to apologise even for something which is not your fault.For example, someone may accidentally tread on your foot in a crowd, but you would be expected to say sorry, even though you are the injured party!
‘Sorry’ is an instant response for most British people, and many non-native English speakers comment on the ‘insincerity’ of the English.
Variations in culture include not only manners, but also topics of conversation.
Acceptable levels of small talk and directness are quite different, even in languages as close English and German. Whilst the English will tend to chat about the weather and ask about family before moving on to more serious matters, Germans like to get straight to the point, moving the conversation to the matter at hand in what a native English speaker may perceive as a rather abrupt manner.
Of course, social conventions change over time. For example, the formality of addressing elders and strangers by their title and surname, which is still common in other countries, is long gone in Britain. It has been replaced by friendly, classless American approach of first names.
However, I once heard an American author describe the difference between people in the UK and the USA. She claimed that the aloof British were like ‘coconuts’; far more appealing once you get through the hard and unapproachable shell to the sweet interior. In contrast, she described the forthcoming Americans as peaches – initially soft and sweet, but with a hard inner core.
These cultural standards are as much a part of British culture as the language itself - but much harder to teach. They are best learnt as part of an integrated study program in the UK, where students are constantly exposed to societal norms and pick up British customs and manners without even realising!