The correct answer to this open question is the following.
Although the question seems to be incomplete because it does not provide any references, we can say that the cultural differences that are likely to arise between Costco US employees and local employees that are working in Australia Spain, and China are the result of totally different cultures, idiosyncrasies, customs, and traditions.
American customers are so different from Australian, Chinese, or Spanish consumers. What works in one country would not work in another. What is success in the US could be a failure in Spain. We are talking about different preferences, tastes, likes, and traditions.
That is why it is so important that Costco branches in other countries survey and understand local people's minds and tastes, so employees in each country can be trained in customer services, local preferences, assertiveness, human and business orientation, and many others.