A lot of the characters were a lot more sassy/mean earlier on in the comics, so it could always be explained as people taking out some anger on him after he cooled down.
A more in depth explanation would be that Charlie sometimes likes to be the victim. He could go talk to the red haired girl, but would rather suffer from afar. He could confront Lucy about the football, but dosen't want to. He could do many things, but he's too afraid to. Its like being friends with someone who likes to play the victim card, or someone who could do many things / chooses not to / then complains and blames the world about not doing it.