This happened years ago when I was like 15 years (currently M/22). 

My mother was picking on me for not doing great on an exam. I totally flipped and told her that at least I'm doing better than her academically (I graduated first place at my school) while she didn't even go to college.

She got all sad, started crying and told me that it was unfair that I was being mean to her while I never was mean to my bullies.

Some context: My mother is the typical narcissistic mother you usually see on r/raisedbynarcissists. I fucking hate that woman for treating me like shit literally my whole life, but at the same time I feel like a hypocrite since she gives me food and a place to live. 

A few hours ago we were talking about christmas, she then started saying that she felt kind of sick and I told her that it could be because she stays 10 hours a day playing candy crush on her cellphone and it was not healthy and that could be causing her the headache. She answered back telling me to shut up and that I was an annoying piece of shit and if I kept talking she would kick me out of the house... 

Then I went back to my room silently like always, and started thinking about awful things related to her and this memory showed up.