When agreeing with someone, most (unenlightened) people bow their head first down, then up. What’s wrong with this choreography? Unfortunately, a bowed head subliminally signifies subservience, sadness, humiliation. I call it the “Beat me again master” position.
Conversely, when your head is held high, you exude self-assurance and energy. Think about it. You throw your head back when laughing, when winning, when feeling full of pride.
On to your notable nod: When you want to nod to show agreement with what someone is saying, don’t nod your head down and look like you’re eating humble pie. Starting tomorrow, nod your head UP from neutral, then back down to parallel. Now you are not humbly bowing to them. You are confidently gracing them with your agreement.