Definition: Given a real-life anecdote of a complex ethical situation, generate a suitable title that describes the main event/root cause of the situation. Imagine that the given text is a social media post, and you have to write the title of the post, so the users can decide to read the main text or not.
Input: This happened several months ago. Sorry for language problems as English isn't my first language.

My wife, our three children and myself own a house with a garden. In the garden, there are two bungalows that, while owned by me and my wife, my parents-in-law have "life estate". They have the right to live there and use these as long as one of them is alive. This was agreed upon when buying the house because my in-laws generously gave a lot of money. They are also free to use one of our four basements rooms for storage.

My MIL is very helpful. She's only there every other week for a couple days as she's still working, but whenever she's there, she helps cleaning up the house, tending the garden, doing the laundry and so on. I have mixed feelings about it, since we don't ask for her help and while I enjoy having some tasks off our plate, she sometimes misplaces stuff while tidying up or rearranging our place.

So once I was taking out the trash and I found some of my stuff in the garbage. I have a small box of memorabilia (personal stuff from my past like letters, my class ring and letters from my mother from the time I spent in the US as a student, a worry stone my first gf gave me, old pictures and so on) that is in one of our rooms in the basement. I found some of this box' contents in the garbage. I went through all our garbage cans and sure found the box itself and all its contents. I was furious. I rescued the stuff - except for some moisture it seemed unharmed - and confronted my MIL, while the family as having dinner. I was really angry for her to throw away my stuff.

She claimed the box was standing next to other boxes that my wife had told her to throw away. As far as I could tell, those boxes were in front of a shelf, while my box were in the shelf. So I told her with so many a little louder than normal words that I do not want her to go through my things.

She cut her stay at our house short and left the next day. A couple days later my FIL lets me know that she's angry at me for yelling at her in front of her grandchildren and my wife kind of wants me to apologize. While I didn't agree, I did apologize, because I like my peace and quite and don't need to fume about stuff like this and if it helps to say words in order for others to feel better, it doesn't hurt me to say words. (I think I did point out that I don't think it's bad for the children to witness an argument, especially because I made sure I explained to my children why I was angry at my MIL as neutral as I could.

So, AITA?

being angry at my mother in law in front of my children