Demeanour is a funny thing. We can sniff it out almost instantly, and when we do, we've already sized up our fellow human.
As a concrete example, the minute you walk into a restaurant, the way you're greeted instantly leaves you with an impression that lasts the stay. It wasn't the fancy decor, nor the lavish spread, nor the tingle of fine, obscure music you've never heard before. It was the behaviour of the human in front of you. That's why you tip extra for good service.
Even when meeting up with a bunch of friends, you can usually figure out really quickly how each of them is feeling on that day. What's important though, is the fact that we can tweak our own behaviour accordingly; for example, to display a more sympathetic posture when our friend is having a bad day.
When applied right, we can behave exactly the right way in front of our audience, to affect an outcome as we so desire. People do this all the time, and those who manage to bring the right face (literally) to the task are oftentimes the most successful.
So that's the colourful personality part. What I'm a little more interested in though, is the grounded principles part. This is because when one fakes it to make it, eventually one loses themselves; the man of too many faces, always wearing a mask .
Hence the need to have grounded principles. It's something that we can fall back on, and something that cannot easily be taken from us. For as much as someone like Gary Vaynerchukworks, he's really clear on this fact: You're fucked without your family.
Unfortunately, what this means is that you can't really trust the current face facing you to be the 'true' face of the person, but hey, that's life. Now if only they had taught me that in school.
 Sting - Shape of My Heart