I've read about studies where just seeing someone else smile and be happy makes others who see it also happier. Like a happy person gets on a bus full of less than happy people and the entire bus ends up happier. I don't think this is really that new, except maybe to the degree it scales the distribution. I imagine words create a smaller impact than a face to face encounter, but I'll leave that to a study to figure out.
The person who mentored me when I first became a college instructor mentioned the importance of appearing warm and engaging on the first day to remove anxiety of the new students. There's probably some truth to that "just seeing someone else smile" thing.
