We express many different emotions using our faces, and that CoVid mask you hopefully wear when leaving home covers up the part of the face that Americans may find most pleasing and rely upon to distinguish friend from foe.
This is because Americans value high energy positive emotions like excitement and enthusiasm, which tend to evoke big open smiles, according to a Stanford University psychologist. And this may be why some Americans don't wear them because it makes them feel disconnected from others.
So, what is the workaround on this? Wear a mask and learn to smile with your eyes and voice, and to read the eyes and voices of others.