Actually, one of the factors that can make an image interesting is that “certain sense of tension”. The rule of thirds is one way of establishing that, by creating an visual imbalance and causes the mind to seek an equilibrium. (Of course, the tension needs to be resolvable – a psychological path to equilibrium needs to be provided, but it need not be obvious, overt, or immediately consciously recognizable.)

Placing the object of focus in the center of a frame may produce an image without any tension (it may become boring) but that would depend on all of the elements employed, because all the subjects, objects, shapes, and colors of a picture are interdependent.