What is the most creepy anime you've watched?

Before you comment let me say that when I ask creepy, I don't mean creepy as in scary or horror, I mean in the sense that it's... uncomfortable to watch. Like you are legitimately concerned for the writers who made it or you wouldn't want your kids within ten miles of them, you know THAT kind of creepy.

1. Aku no Hana

2. School Days

3. Happy Sugar Life

4. Black Lagoon

5. Pupa

6. Narutaru: Mukuro Naru Hoshi Tama Taru Ko

7. Paranoia Agent

8. Made in Abyss: Retsujitsu no Ougonkyou