CBS News: With more than 777,000 Instagram followers, teenager Essena O’Neill thought she had everything she ever wanted. Last week, she changed her mind. The 19-year-old Australian broke down in a viral YouTube video to explain why she’s quitting social media, shutting down her Instagram, Tumblr and YouTube channel. In a caption on her video, she explained that she had “contrived” her “amazing life/body/self.”