One of the things we can easily observe by paying a lot of attention to the interactions between human beings in Australia is that they take their time to adequately close a conversation. They also seem to always manage to consult everyone involved to make sure everyone is happy with whatever that seem to be nonstandard and happen during that conversation.
In places like Brazil, such a concern is inexistent: People simply hang up, like if one person says nothing after the other released some information, then the other simply hangs up.
During the interaction, people are trying to be as useful as possible to each other and that includes solving problems for the other person in order not to bother them.
We can easily understand why that is rude: Everyone is a grown-up and expects being consulted before any nonstandard procedure is adopted, so that nothing that is not of their taste happens there.
Sometimes it seems to be impossible having both cultures existing in a peaceful manner, since the choices of action of the subjects in a given situation may oppose each other.
Who is there to teach us such differences?
Who will ever be?
We should definitely invest more on cultural adaptation and cultural information. We should also invest more on cultural studies.