You shouldn't chat about personal things during a meeting.
Alice is in a board meeting with many coworkers where the CEO is explaining a new business plan.
Alice wants to tell a coworker a story about what happened last night.
Alice waits until the meeting is over and tells the story on Alice's break.
Alice gets the attention of the coworker and begins to tell the story loudly.
everyone continues working efficiently and without interruption and learns the new information.
Everyone is the room is disrupted and Alice is seen as rude and unprofessional and reprimanded later.