-An expression said aloud to someone to let them know you know already.

-Used in a sarcastic tone of voice, often rolling your eyes upward gets the point across better. It can be a bit insulting too.

-Its like saying "why did you waste your time telling me that" gesture.

When someone thinks they are the main character of their life. Usually comes with a side of individuality complex, quirky style and a self centered point of view.