Dreams can occur anytime during sleep. All the dreams occur during deep, REM (rapid eye movement) sleep, when the brain is most active. Some experts say we dream at least four to six times per night.
Theories why we dream is those that suggest dreaming is a means that the brain develops emotions, stimuli, memories and information that's been processed throughout the waking day.
A theory about the purpose of dreams is that they help you store important memories and things you've learned. They get rid of unimportant memories, and sort through complicated thoughts and feelings. Research shows that sleep helps store memories.
Dreams don't actually mean anything Instead they are simply electrical brain impulses that pull random thoughts and imagery from our memories. The theory suggests that humans make dream stories after they wake up. This is a natural attempt to make sense of it all.
In conclusion, dreams are stories and images we create while we sleep. They can be many things such as entertaining, fun, romantic, disturbing, frightening, and sometimes bizarre.