Many people have several dreams each night. Dreams are like short films, they are usually in colour. Some dreams are like old films. They come up over and over again, that maybe the dreamer is worrying about something.
Dreaming may be a way of trying to find an answer. Some people get new ideas about their work from dreams, they may have been thinking about their work all day. These thoughts can carry over into dreams.
Too much dreaming can be harmful. The mind is still at work when we dream, that is why we may have a long sleep and still wake up tired.