To dream that someone is shorter than you indicates that you may be looking down on that person. You feel that you are above her or him. Alternatively, the dream represents authority and pride.
To dream that you are shorter than everyone suggests that you have a tendency to overlook things. Perhaps you feel that a higher power is always looking over you and judging your actions.
Alternatively, the dream denotes low self-esteem issues. You are looking down on yourself.