Perhaps the most stunning discovery in relatively recent behavioral neuroscience is that we all have mirror neurons in dispersed areas of our brain, and these mirror neurons are constantly paying attention to other people and their emotional states. Once they identify the emotional state of someone else, guess what? It mirrors it!
It mimics it, and then we feel it too. It's called emotional contagion. This is why stress can be contagious.
If you go home to your family and you're stressed, you might notice that they become a little stressed too. Or, if you go home and a family member is stressed, you can't help but feel it rub off onto you. But similarly, it works for the positive side of the emotional chart too.
If you're showing up energized, pragmatically optimistic, and enthused, others will actually catch that.