There were a few times I've seen duals (usually at the beginning stage) try to compete and one up each other, but usually, if they don't leave and stick around within a few months they really love each other because of this whole thing that if you don't have a dual while growing up, you yourself try to assume your dual's role in your own mind (like a psychological coping mechanism). Because of this, you have a hard time relinquishing control and recognizing that your dual is naturally good at the thing that stresses you out. Once the roles/tasks are divided within the dual pairing, the relationship is very wonderful.