Many managers and supervisors have an “open-door policy,” but because of the atmosphere that they create, no one ever walks through the open door.

When someone has a problem or needs help, they walk up to the door, just about to walk in, and they see the negative countenance.

Most people just turn around and decide to come back later.

A neutral expression can be just as unconstructive.

People don’t like to guess whether someone that they work for or work with is in a good mood or bad mood.  A genuine smile can do a lot for you and for the people around you because it will make you more approachable.

Smiles are also contagious.  One well-placed smile can go a long way to improving morale and building rapport.

Week #1: Build Trust and Rapport Quickly
Principle #3: Smile More
https://www.leadersinstitute.com/daily-leadership-tip-3-smile-more/