Really Necessary Information - When someone randomly states something often pertaining to their own interests which has absolutely no relevancy. RNI is information typically about one's self that nobody needed to know or cares about.
"The silence was interrupted by Tina and her RNI, telling everyone about how fed up she was that her favourite streamer was doing the third consecutive stream on a game she didn't like. Unfortunately for her literally nobody cared."
Someone who makes frequent mistakes, and overlooks important details very often.
"Jamie always brings peanut butter cookies to my party, despite my constant reminders of my allergies to them. That mongatron!"