Answer:
Symmetry is obtained from an axis or a point, where we see equal or practically equal sides. Symmetry is pleasing to our eyes, it gives us perfect harmony, because many things are naturally symmetrical - our body, for example.
It is true that there is some visual comfort when it comes to symmetry, but that is not why it needs to be monotonous. Symmetry is synonymous with stability and balance, so we see many more traditional layouts using only centralized information. Although this does not classify design as tedious, we can use symmetry without falling into this trap which is a comfortable design and without risk or dynamism.
Proportion is one of the standards of classical “beauty”, being in art the ability to relate two or more different measures on the same support. Measurements can be determined by the (geometric) relationship between width and height in the same object, or of this relative to another.
Since ancient times the golden ratio has been used (theoretically) in the arts, architecture and of course also in Design. Some claim that it is possible to find it also in other segments such as Beethoven's ninth symphony (which would have been based on this reason), Masonic plays, purse actions, the proportion of the human body and nature. It has also been cited in pop culture literatures, such as the Da Vinci Code Book.
