From the time of Sigmund Freud , a lot has been written on the dreams ant also about the “Interpretations of the dreams “ but still difficult to comment scientifically about its content.
But if a person encounters with important persons, or happens to get involved in various ways… stressful or other wise, if a person goes to bed with these images or tries to suppress some issues… these manifest as Dreams when brain sensors stop controlling them.
May be if you focus on a quiet place, on that imagine of that person you may find some cue to connect your thoughts regarding that person.
Health Tips
You may like to get the help of a mental health professional, if these “Day time dreams of nocturnal dreams “ become bothersome.