Everybody's done this, unless it's just me, then someone should let me know. You walk into a room that's so quiet, it could be empty, but it's not empty, because you're in there. And someone else. Now, that person isn't your best friend. You know them, but not that well, like, you share a class together or something.
This place COULD be the very classroom. It could be a break room. It could be an empty hallway in front of your class, the bathroom, anything.
Since this person isn't my best friend, but I know them, and they know me, some kind of greeting or reaction seems appropriate, otherwise it's obvious that I'm ignoring them or something, especially if I noticed them. And it's not acceptable to converse with them because we have nothing to talk about, especially since we've never talked before.
So here are some reactions to this situation.
The raised eyebrows, big eyes, and wave, usually accompanied by a teethy frown
This look is one I've used, and I've seen other people use too. The person makes this face and then walks as if they're tiptoeing through slippery mud. This look conveys "I'm tired and the day isn't over yet."
This one, while seeming natural, is perhaps the most awkward. This word breaks the silence and rings through the air, making it painfully aware how very quiet it is. There's nothing to talk about, but you can feel words choking in your throat, unsure of whether to be spoken or how to be spoken or anything.
So you purse your lips. But purse them so hard the actual lip disappears completely. No more lip. Ta-dah! Your mouth is still there, but the pinky-ness of your flesh shows a weakness, and you must not show weakness to your peers. What remains is a thin crack in your face, where your lips used to be, the outside of the crack on the far edges full of "c" shapes, echoing so far across your face, it goes all the way around your head. Accompanied with this is a quick raising and lowering of the eyebrows, while simultaneously nodding your head.
I've never done this one. I don't get it, and frankly, it bothers me. It happens to me a lot. I walk into a room and the person in the room chuckles faintly towards me. I know it's towards me because they're looking directly at me, and the chuckle doesn't happen unless they notice I'm there. OR I'm sitting in said empty room, and the person walks in and goes "Haha! AHHHH!" And raises their hands above their head in exasperation. Only certain people do this, and it usually scares me. I think the certain people who do this are serial killers. And cereal killers alike.
This is my safe go to. All that goes with this is a nod, usually a deeper nod than you would do to say "Yes", more like you're bowing to them.
Well there you go. I'm thinking about discussing hug reactions next.