Imagine a scene where two people are trapped in a box with no light from which to see each other. They are strangers to each other and do not know what the other looks like. How they got in the box is important if the reader is to know the origins of their plight or if it has something to do with how they are to escape. As for any scene where the characters are bounded by walls, there should be purpose to their observations and dialogue.
A scene with many children in a room together should explore their surroundings when it is necessary to further their development. I suggest creating a picture of the scene in your mind and try to imagine what the children or child is doing and why? The purpose of any scene is to further the development of the story and should be filled with the essentials necessary for the reader to feel as though they are there without being told they are there.
This brings up the sticky point of telling vs. showing. A tell tale story will leave the reader with lots of dead air space while they digest their dinner. Whereas a story that limits the amount of gazing and staring will keep rolling along much smoother.