There may be some truth to both ideas. Those who think dreams all have meaning, study the situations, places, people and objects in dreams, and then interpret them. They try to figure out what the dream meant to the dreamer. Some people believe dreams can predict the future, but studies have never proven that to be true, mainly because it is difficult to study dreams in a laboratory. Almost everyone has nightmares sometimes.
Many people can force themselves to wake up when they have a bad dream.
It was once thought if a person was falling in a dream and hit the bottom, or ground, they would die. There is a way to help yourself have good dreams. While falling asleep, you can start thinking about a happy situation and, often, a dream will begin from the happy thoughts. Doing this is called giving yourself pre-dream suggestions. For example, think about riding a pony on a mountain.