There is a reasonable chance that in number of years from now, everyone you know will be looking into virtual screens that only they can see. You will be too.
Some of these screens might be visible all the time. Others might just pop up as needed, such as when it’s time for an appointment, or to show the way to a subway entrance around the corner.
So you will know that other people are seeing things that you cannot see. And they will know the same about you.
I wonder what sorts of social protocols will evolve around this capability. Perhaps there will be some movement of your head, or some flicker of your eyes, to indicate “I’m not actually looking at you right now, I’m looking at a screen.”
But it might be something else entirely. I guess we won’t know for sure until it happens.