Cultural Curiosity

There's a strange feature of Xhosa culture, found here and there, which I have never been able to work out (I am married to a wife who is largely of Xhosa descent). One attributes actions to the next person. Spill your drink, say, and you say to the person next to you, You spilled my drink. OBSERVATION: It's not really blame. It's not in that spirit, and sometimes it's not possibly in the context of blame. There may be something similar in English, though. For example, We don't have very good manners tonight, do we -- where one is not really referring to "we", but to a specific person in the room. This may also be the case with positive meaning, for example: We are well dressed, aren't we.