For some unknown reason, Millie is obsessed with being best friends with Louise, despite Louise's hostility. She typically wears a giant ear-to-ear smile and maintains a very cheerful-yet-creepy attitude. She speaks softly but constantly, rarely letting others get a word in edgewise. When interrupted or pushed too far (typically by Louise), she loses her cheerful disposition and becomes sociopathic while still maintaining her giant grin, stopping at nothing to get her way.