 MGM boss Louis B. Mayer treated him like a son and saw in Rooney "the embodiment of the amiable American boy who stands for family, humbug, and sentiment," writes critic and author, David Thomson.By the time Rooney was 20, his consistent portrayals of characters with youth and energy suggested that his future success was unlimited.Thomson also explains that Rooney's characters were able to cover a wide range of emotional types, and gives three examples where "Rooney is not just an actor of genius, but an artist able to maintain a stylized commentary on the demon impulse of the small, belligerent man