Design is the unity of dissymmetry and symmetry

Most of people favor symmetric placement of objects in layouts. This is natural feature of mind. People also favor when human body is symmetric, hands, eyes and legs have the same size. Any disproportion makes body ugly. Preferring of non-symmetric bodies is kind of perversion. That is why we have to make the alignment and distribution of layout parts. Objects have to be kept on the same distance one from another. The gap from left/top has to be the same size like the gap from the right/bottom. This rule can make any website acceptable for the most of users. On the other hand the inner world of human being is beautiful if it is non-symmetric. When people think symmetric they are boring. Symmetrical design makes layout stable and dead. We have to put disproportion in weight of webpage objects to make it dynamic. But these parts still have to be symmetrically distributed and aligned in the same time. Neglecting of symmetrical borders and distances between objects can be used for design perversion of website.

 This is the bad way to put pictures on the header because they are very boring. It is better to put them on dynamic desymmetric slider like on the next picture.

You can see that outer margins are the same and symmetric but weight of picture makes website alive.

The same size of columns are not good also.

Disproportion in columns of Harvard Graduate School of Design website

But still all these parts are symmetrically distributed and aligned