Excerpt from: Every Dream Interpreted. Pages 76-77: What kind of dreams do most people have?

What kind of dreams do most people have?
Bad ones! Because happiness in dreams is rare, dream researcher, Ernest Hartmann, decided to study happy dreams. He found that in most of the dreams in which the dreamer experienced some kind of good fortune, he then began to worry about it, or the good fortune turned into a misfortune. It seems that dreams focus most on more difficult emotions.

Many studies have found that if you were going to predict your next dream, you'd be most successful if you guessed that it would contain you and two other characters. (These two would probably be adults, as in 90% of adults dreams; if you are like most dreamers, you're alone in only 15% of your dreams!) Your next dream is most likely to occur inside in a building of some kind, not your own home. The dream would contain hostility and be generally unpleasant. In about two-thirds of most people's dreams, a misfortune strikes or anxiety is felt. This percentage is larger for sex dreams, which often end badly, reflecting performance anxiety, relationship fears (being trapped or left), or fear of being caught.

Sexual dream experiences are somewhat rare, occurring in 10% of young men's dreams and 4-8% of women's. These frequencies may increase toward middle age, with, in one study, 30% of women's dreams containing explicit sexuality. (See pg. 84-87 for differences between men's and women's dreams.)

Most common human dream
Here's a dream that exemplifies the most commonly occurring dream of any human adult, living anywhere: I am inside the communal hut/coffee shop/neighborhood bar. My friend and a stranger are with me there. The stranger begins to argue with me, then gets up. I run away toward the door to the hut, but then it falls to the ground with a loud noise. I am afraid.