In your definition of a friendly relationship, you also must consider the perception of the other side. I'll explain what I mean. In certain cases, it would be rude, if not insulting to the other party, to refuse the offer, either because of the logistics involved, or because it would be related to the hospitality being extended.
Since this is a bilateral relationship, where two parties are involved, did you take into account the cultural or ethnic aspects that are necessarily a part of what are inevitably international relationships, at least in the Prime Minister's case?