Do you have a Resting B*tch Face or other neutral resting face in classroom while teaching?

Saw an interesting YouTube interview video about Body Language and how it's used in daily interactions.
There was a segment about Resting B*tch Face and other neutral resting face.

With that said,
What is your resting face when you're in the class and not talking.

How about always smiling?

Have you been told by students, teachers, school staff, vice-principal, principal or even by the company that you look (emotion) due to resting neutral face.