I am a pathetic, aimlessly malcontent shitstain

I live with my parents. While watching the movie Wanted on a Netflix-shipped DVD, my mother had a hard time keeping up with the narrative and kept asking questions during the movie. I grew frustrated and answered her questions, then ended each reply with a febrile scolding for her not keeping up with everything occurring on the screen. I was yelling at a woman who raised me to be a proper and functional human being in society. Not easy, teaching them kids. How to remain polite and decent in public. How to be honest and just generally good. I shouted at my mother who was trying to understand the movie at her own pace, through her own ears but needed a spoiled American kid to help her keep up with the car chases and a film's final twists before the spinning denouement. A Thai-American woman who can carry on a great conversation but is always silently cursing herself when she encounters a word she doesn't know or didn't catch the first time around. She'll pretend she understood and keep that smile for you to accept her as someone you should talk to. I hurt this woman yesterday evening and she'll forgive me for it.