Sean Penn was a sudden guest Friday night on the Charlie Rose show to talk about Marlon Brando.

Near the end of the conversation, Rose brought up that Penn and Brando were similarly grim and wondered where it came from and what it meant.

Penn's reply, and this is paraphrasing, was about what a friend told him.  He said that he has this great friend and one day his friend was walking through an airport with a grim look on his face and was then asked why he was so grim all the time and his friend's reply was something like, " knowing all I do makes me grim" or "knowing all of this makes me grim." 

I can't recall the exact wording, but I was wondering, what Penn said his friend said sounds like something David Baerwald would say.  Does anyone know?