one thing i really like is how they obviously went out of their way to match asahi's speech patterns with his and yotsuyu's father. the guy is a minor NPC who barely has any lines, and yet despite him being an old man who doesn't particularly look like asahi he uses the exact same inflections and tone of voice. you've already been listening to asahi being a creep this whole time, and then suddenly if you're paying attention it becomes so clear where he got it from. he really does just sound exactly like his dad.
(and it makes absolutely everything about the situation that much more skin-crawling, considering what their father is actually saying in the scene where that stands out the most.)
again, minor NPC with very little screentime; it would have been easy for them to just give him A Voice and be done with it, and instead they took the opportunity to imply volumes about asahi and his dynamic with his family in such an effective, understated way. anyway the naeuri siblings are ruining my life