The art of acknowledgement
Nothing makes people more uncomfortable than not feeling acknowledged.
That's because we're born and bred to connect, to fit in, and to take notice.
Noticing that we've been left out, overlooked, or ostracized is akin to indefinite isolation. (Not a great place to be on the Savannah, or in modern life.)
Better then, to invariably let people know when we see them, to intentionally show that we care, and to give them the recognition they need to let their best selves shine through.