But in fact, no one really knows the precise function of dreams. One thing's for sure, though: dreams are very, very strange things. Keep reading for six fascinating facts about dreams and dreaming...
Most dreams aren't very sweet. In fact, dreams tend to be pretty darn unpleasant. A 2008 study confirmed that our dream experiences are negatively biased. Some studies suggest that we've evolved to dream about scary situations more than positive ones because that prepares us for survival in case we come across a threat in real life.
"If you missed a threat, you were lunch," Dr. Ross Levin, a psychologist and sleep disorder specialist at Yeshiva University in New York City, told Reuters. "The 'default' dream is basically the bad dream."
Dreams can be a "warning sign" of health problems. Just because you have a nightmare doesn't mean something is wrong with you. But a recent study showed that nightmares are sometimes linked to heart conditions and migraines.
Also, "any infection increases the amount of slow-wave sleep we have, however, this delays the starting point of when we enter dreaming sleep, so dreaming sleep starts late, and can erupt into consciousness," Dr. Patrick McNamara, a neurologist from Boston University Medical School, told the International Business Times. "This leads to vivid dreams and strange hallucinations.”
'Wet dreams' affect women too. While it's easier to find evidence for men having orgasms during their dreams, women have them too. In a 1986 study of university students, 37 percent of women reported having had a nocturnal orgasm.
Dreams paralyze you--but only temporarily. During rapid-eye movement (REM) sleep, our muscles become paralyzed -- a good thing, since that keeps our bodies from acting out jumping, running, punching, etc. Research has shown that two powerful brain chemical systems work together to paralyze skeletal muscles during REM sleep.
You see more than you hear. Dreams tend to be more visual than auditory, and more auditory than stimulating to the touch, Dr. Robert Stickgold, director of sleep and cognition at Beth Israel Deaconess Medical Center and a Harvard Medical School professor, told The Huffington Post.
We all have them... every night. You may not always remember your dreams, but scientists say we all dream at some point during sleep. The only exception is if you're suffering a disease or brain disorder of some kind.
Craving some more dream facts? Check out a slideshow and "Talk Nerdy To Me" episode on why we dream below.