M(27) F(27) Yesterday my girlfriend and I were having dinner, she had cooked hamburgers on the stovetop and we had some poor mans turkey burgers with sourdough bread, baba ganoush and spinach. At the beginning of the meal she said she wasn't very hungry and would only have one burger, me being a bigger guy had two. I made my second burger and put all of the leftover spinach that was in the bowl on it. After I had finished eating my girlfriend got very mad at me and said that if I was gonna take the last of something the courteous thing to do would be to ask if anyone else would want some before killing it. I asked her what she meant by that and she said that she had decided in the past 5 minutes that she wanted a second burger. I then said that be that as it may she had told me at the start of the meal that she only wanted the one burger and that I had assumed that seeing as she wouldn't be having a second burger it wasn't an issue taking the last of the spinach without asking. She got very angry and we had an argument about who was in the right about this. I tried to explain this in another way saying that its the equivalent of us eating cereal and then her saying she doesn't want anymore and me taking the last of it. We still have about half a bag of spinach in the fridge so it wasn't really "killing it". She was adamant that she was in the right about this. AITA?