positive and negative memories are stored in different parts of the brain. but all of them often appear in our dreams as a result of brain activity. sometimes you're not sure was it a dream or a memory.
"it was a dream" represents that kind of a memory from your childhood or from the distant past that you cannot remember well, but you remember the feeling of happiness and joy. it represents the moment of realizing that some of your memories are misrepresented, so you know clearly: it was a dream.
35mm film photography taken with FED-2 and Zenit ET on Kodak 200 film intervened with digital double exposure.