For example, we had one artificial Christmas tree, it's perfectly fine if you like that sort of thing. I mentioned getting a real tree this year. I come home the next day and there's a NEW artificial tree in the room. We now have TWO artificial trees. I would have preferred talking about that in advance.
This is typical "power struggle" in place. You actually talked about that in advance, and she showed you who is in command. The point was not to buy a new artificial need (there was no need anyway). The point was "who is in power". If you think it's a Christmas tree question, I think you are deeply mistaken