Why am I not surprised by today's events?!

On Thursday my aunt visited my mother (her sister) as usual. Aunt in "bossy" mood, commenting that mother still had Christmas decorations out, then was rude to her. In a phone call yesterday evening and in person today, my mother was complaining about my aunt's attitude. Somehow, the conversation expanded to include situation with my brother and SIL. Mother's accusatory tone caused me to remind her about comments in early December, about me apologising to SIL for her lashing out at me. Mother denied it, then suggested I get the bible so she could swear on it. Culmination was mother's tears, possibly done to make me feel guilty/admit lying (which I wasn't).

It's nothing new, but realise my mother is a coward. She finds it easier to berate me for the actions of others. What I've said now is that as soon as anything unacceptable is said, then I will deal with it at the time, not some weeks later.