The principal of staging.
Staging basically means that everything within a scene is in place and decipherable to an audience. For example, a long shot of a soldier walking up to his home, finally coming back after a year away overseas to his unsuspecting wife. To make the scene clear the shot should include the soldier smiling hurrying towards his home, he is excited to be back with his loved one. He rings the doorbell and waits, the shot should then focus on the face of the wife so that her emotions are shown, which would be shock, happiness and she bursts into tears clutching him as that shows the pain she went through after months of being alone. Through viewing the expressions and environment of the characters one is able to understand the story of what is occurring within a scene, this is the principal of staging and it is incredibly important in animation as well as in general acting.
If a scene is muddled and it is not clear how the characters are feeling as they do something then the audience is lost on what is occurring thus losing them.

Character shows fear as he backs away.

Character turns to run and then steps on rake.

Character is promptly hit in face with said rake and knocked out, easy to understand.