As the a famous saying goes: Do as they do at Rome. The knowledge of local custom can help outside person adapt to the new environment rapidly. Moreover, each place has the own unique culture, may keep in touch more ideology and culture through the local folkways and customs. For instance, a Chinese people came to Britain, he can imitate British life style. In this way, He can understand British habit more thoroughly, thus, make himself live a more comfortable life in Britain.
On the other hand, the outside thought has a lot of positive influence on local culture too. For example, the outside thought could bring the new theory and inject vigor into local culture. The exchanges of outside thought and traditional culture can help people to find out about the culture of other areas and countries.
Making a general survey of human history, it is a positive trend that the nationality has been merging all the time. So, we should not only propagate local culture for the outside people but also study outside culture and custom. In this way, the earth would become a family, all the people would get along harmoniously.