I hear always this phrase on anime...

***********

Nanto iu koto desu .     Correctly, you should be  iu. but you can hear "you"

If the person asks a question,   "What do you mean by that?"

If the person gets angry,  

"What hell are you doing?"

"How dare  you!"

"What a mess!"

Do you always hear it on anime? 

hahaha, someone seems to always ask questions to his or her mentor.

Or someone seems to be always astonished by someone.

Enjoy Japanese anime!