Freud hypothesized that while dreams try to communicate deeper aspects of ourselves that we are not unaware of consciously, another part of the psyche fights against this simultaneously.
This censoring part of the mind only lets these expressions through symbolically, trying to find a balance that allows the emotional expression to be satiated while not allowing the conscious awareness of what or where these emotions come from–this is dream censorship.This usually occurs by way of masking harmful content in dreams symbolically.
An interesting experiment to do regarding this is to write down as much of your dream as you can recall upon waking. Then cover it up somehow. Later in the day, write it again without looking at your previous entry.
Do it again towards the end of the next day. See what changes, and what has been entirely omitted. Oftentimes, what has been censored is what is most important to interpretation.
Free dream interpretations