Just like some people said, Brad Pete fit in the role well, actually it seemed that that kind of 'I am a stupid ass and I will mass up' feeling existed throughout the film, and even affected my perception of his acting when watching Benjamin Button.
Think carefully, there are trumendous amount of similarities between Benjamin and Chad. Some queird plans, the habit of showing body, especially the so called 'world best Aub' and at last, the annoying and blurring accent.
Brad Pete is good at being normal people, like Benjamin Button, or the intelligence disabled, like Chad. This is not a good sign, just like when Ge You started to do his disasteruous 'Dinner'.
Just imagine, in near future When Our lovely Pete took apart in a new project like 'Watergate', talking to and threatening the politician. The first sentence we are expecting should be, 'R~i~chard Ni~xon? I have some thing important for you.' with his hilarious fake voice.