Dreaming may seem to be the best part or the worst part of an individual's day. Some people don't even think they dream at all. The truth is there are both psychological and physiological reasons for dreams. 

https://greatergood.berkeley.edu/article/item/why_your_brain_needs_to_dream

https://www.counselling-directory.org.uk/memberarticles/the-importance-of-dreams-what-they-can-represent