YMMV / Penny And Aggie Missing Person Cyndi And Charlotte
Base Breaker: Right up until the strip that confirmed Cyndi's Complete Monster nature, there was considerable, even heated, debate within the fandom as to whether she or Charlotte was the worse person.
Creator Breakdown: When a reader asked Campbell whether it had distressed him to get inside Cyndi's mind and think like a person with antisocial behaviour patterns, he stated that it was disturbing to get into both her and Charlotte's heads and that it made him "a neurotic mess" at times. He also revealed that he based the toolshed on the one in his parents' yard, and as a result developed a phobia of it.
Memetic Mutation: "Hee." Although Cyndi's signature sadistic giggle had appeared a few times before, its appearance at the moment of Charlotte's suicide attempt solidified its association with Cyndi, such that it appeared often in Fan Fiction, and became an in-joke on the forum (e.g., lampshading one's avoidance of typing a single "Hee" in a post lest it give the appearance of Cyndi having written it). Campbell himself said that he nearly had Daphne say "Hee" in this later strip, before realizing how readers might take that, whereupon he changed it to "Heh."