8 People Whose Ambition Came Back To Bite Them Ambition is a good thing! If we didn’t believe that, this website wouldn’t exist. But success-mania is also a double-edged sword. In J. Edgar, which opens this weekend, Leonardo DiCaprio plays long-time FBI head J. Edgar Hoover, whose drastic overreach and secret investigations tarnished his legacy irrevocably. That got us thinking about people — re..