The power of dreams:
A dream is rooted in the level of Soveiv Kol Almin, in which there is no order or regulations to which things are bound. In this level a ship can fly in the air and one can be in two places at once. Although, on the outset, a dream seems to be a figment of imagination which is both silly and unrealistic [i.e. Koach Hamidameh], in truth dreams are rooted in a much higher spiritual level than one’s conscious thoughts. One’s conscious thoughts are controlled by his mind, and regulated in accordance to its perception of the world, and cannot perceive beyond the natural order of the world. This is called “Koach Haseichel/Power of intellect.” However, a dream can contact the subconscious level of the soul and give one revelation of truths that he is unaware of. This is why the Torah expounds on the dreams of Yaakov and Yosef, as it shows that they were in contact with a much deeper spiritual level than can be grasped by the conscious mind. Nevertheless, most people don’t have the insight to understand the dream’s cryptic messages or revelations, and that is why specifically Yosef Hatzadik was praised with this ability.
 Torah Or Vayeishev p. 28b