What did my departing neighbor expect me to think?

Ok I had two next door neighbors (some guy and his girlfriend) for the last couple of months that although I detested them both, behaved decently enough for me to keep it civil with them. Two weeks ago one of them broke the curtain frame over the bathroom window and didn't do anything towards fixing it or even apologizing, and four days ago one of them melted down the stick of er I had in the shared fridge to have something soft and gooey to put on their bagel, and then put it back in the fridge like I wouldn't notice. Then they both vanish until tonight when the girlfriend comes out and politely tells me that she has some people over tonight and ured me she will keep things quiet over there and told me that she will be moving out tomorrow and that the guy has already moved out. I listen dispionately as she told me this and confront her about wrecking the er I had in the fridge to which she proclaimed her ignorance but said sorry even for something she allegedly knew nothing about and by extension had no hand in doing, even as I showed her the molten blob in the er tray I threw in the trash when I saw it 4 days ago. Did she expect me to get all misty-eyed at the fact her and that guy were finally leaving? Was some sort of kind words expected from me? I can't see how two people can go from not giving a ____ about a thing to being all polite and mindful all of the sudden.