When they were kids, Kido tried wearing a skirt, then Kano flipped it, reminding her of her bad memories, so then she punched him and reminded him of his bad memories, so now they go back and forth and are the only ones who will treat each other that way because no one else can understand better than each other and think that it’s alright because they can grow up and move on from their horrible pasts together and yeah that’s basically how they’re relationship works.