In portraits that tell a story, it is often good to add a background person. The background person can -no, should– be blurred out; an almost ghostly appearance whose presence adds storyline but also adds questions and interest.
Like in this picture at a recent event, where the incoming president praises the outgoing president:
A story, all in one picture.
When you shoot, always ask “what is my background? What is it contributing? Is it adding to the story or distracting? What is the story?