Thinking what a horrible noise 10 girls age 8 and 9 can make, if they decide to go screaming all together.
Shrill screaming makes me angry. Thank god I never had kids! 
Guess I had it coming, planning a birthday party with the theme "Scary".
In the end it was too much for my girl, she was in the hallway, covering her ears. Luckily they all calmed down with a funny story about a stunningly beautiful and dangerous witch. Completely silent, all ten of them.