This is a scene that disappointed me about Chuck when he belittled Casey for serving "the greater good" and called him "a robot". There are a number of scenes where Chuck says things like that throughout the series. To me it makes it hypocritical when Chuck decides to become a spy; and it is self-serving for him because he does it only because he thinks it will let him have Sarah.
I mean not really true. Sarah begged him to run away with her, and he said NO so he could be a spy. He didn't just do it to get the girl, he had the girl and he turned her down. But yeah, super hypocritical because at that point he makes the same "greater good" choice as Casey. Or I guess it could be seen as character development rather than hypocrisy.
To be fair, Chuck's life was turned upside down by the U.S. Government as they kept sending him on missions and not helping remove the intersect. For the first two seasons, Chuck never really trusted his handlers, right up until Sarah had to betray the CIA to save Chuck.
