I always found Will’s headshake after Hannibal says “do I need to call my lawyer, Will?” cute and oddly comical considering the intensity of the situation.
I mean the degree of headshaking, it’s almost like Will’s a child being lectured by Hannibal.
Like, “Do I need to discipline you, Will?”
“Nuh uh.” *shakes head*
I think this demonstrates the degree to which Will is willing to go to preserve their relationship. He wants to please Hannibal, and not disappoint him. It also shows the amount of control Hannibal has over Will.