I think the major issue is the iciness.It may not just be the greeting,it could be that there's no form of pleasantries shared at all and the person is living in their house,being catered to etc It would feel a tad uncomfortable and knowing how respect is tied to greeting for our people this would be a bitter pill to swallow for the op
I force myself to greet people I don't like even though my face and heart revolt(I ask myself why I even bother).

For the pot issue,different strokes for different folks.Some people view the kitchen as a sacred place,their domain..especially where Daddy eats a special part of the meat.Remember Nigerians are superstitious.Imagine coming back to your house and finding a red ribbon tied to your gate .I had a friend who's mom used to pray against cats.
In a situation like that,a stranger or a relation who is frosty or totally ignores her cannot just waltz into her domain and do as he/she pleases.
Their life,their right to choose what to guard against in their homes.

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HE DOESN'T REALLY UNDERSTANDS THAT HE'S JUST A VISITOR. ANYONE UNDER YOUR RUFF SHOULD PLAY BY YOUR RULES. WHAT'S HE DOING THERE ANYWAY?