Could anyone of you people who typed Snape explain why you believe him to be an INTJ?
Just because he is smart, cynical etc (possesses what we associate with INTJs) it does not make him one.
I am good at listening to people and making them feel alright and sometimes even motivate them. Does it make me a ENFP? NO!
Stop typing people because he has qualities an XXXX have and because you have a XXXX friend who behaves just like him/her.