I kind of see where CC is coming from, but I don't think I'm as angry about it. The clothing store thing didn't make sense to me either. But the interrogation I thought was fine. They address saying each other's names in the story. And the slapping kind of made sense just because smart or not, MC is still a kid who learned who he is literally 3 days before, and doesn't have experience yet how to handle such things. It was also addressed in the story that he behaved that way because he saw a lawyer character in a game he and Emi had in common.