You are looking around the room, people watching. Your eyes dart from person to person, making an assessment of each one in turn, imagining what they are thinking, who they are looking at, and what their secret dreams are. All is going well until somebody's eyes turn suddenly, and they look back at you.
Your eyes meet for one millisecond, and then you blink hard. When your eyes open again, they are neatly focused on something else in the room and you have carefully kept your expression exactly the same. They didn't even notice that I was looking their way, you think, trying to believe that you've just been awfully sly and clever. But all along you know that the one millisecond gave you away. You were just caught red-handed.
The more you think about it, the more you wish that you had not looked away. You wish you had simply smiled, in acknowledgement that you were both just caught staring at each other. Everyone looks around and
But you didn't and now it's too late.
You feel a little embarrassed by your lack of honesty. And you go right on pretending that you never looked at them in the first place.
It happens to everyone.