Pretned all you want, it rarely accomplishes anything.
To give a false appearance of something, or claim/allege insincerely or falsely, will only be playing make-believe.
Dreaming on the other hand, presents a condition or achievement that is longed for; an aspiration. Which denotes something within ones grasp, even though at the time it might not be a reality.
Dream away my friend, i shall be dreaming with you.
But if you pretend, I shall pretend we are dreaming, in hopes that if we pretend hard enough, it may become a dream.