It is important for international managers to understand the cultures of the societies in which they work because it will allow them to be better at managing their workers and understanding their business partners.
Different societies have different cultures. This means their people might have different attitudes towards authority or different customs regarding how those in authority should treat their subordinates. They might have different attitudes towards explicitly telling others what they think. These different kinds of attitudes can affect businesses. If managers do not understand local ideas about relations between subordinates and superiors, they might give offense to their workers. If they do not understand local attitudes towards things like saying “no” they might think they have agreements with partners when in fact they have none.
In these ways, it is important for managers to understand the cultures in which they work.