Crying is the expression of an emotion and emotions in dreams are usually just as they are. There are no hidden meanings to emotions.
If you are crying in a dream, what are you feeling? Are your tears of joy, despair, frustration, or fear? This is what you are feeling under the surface of the real world.
If you witness someone crying, why are they crying? Can you tell what they are feeling? This represents your own feelings that you may not be giving consideration to. It's not you in the dream because it is actually just a part of you with this emotion. Other emotional points of view are more powerful.
