Symmetry: the quality of being made up of exactly similar parts facing each other or around an axis.
When something looks visually pleasing there is often a level of symmetry involved. Perfect symmetry though, can confuse the eye. Adding a focal point to direct the eye is essential if there is an element of focus that should be created. Symmetry can also be lost if there is no object to focus on. Don’t let perfect symmetry take over the image. Let symmetry contribute to the overall goal, but not be the leading scorer.