[whalesalad]

This is a very important concept to understand in visual design too. Sometimes perfect alignment, symmetry, etc... can be the wrong way to do something. Hardly anything in nature is 100% symmetrical. These are sometimes things that go unnoticed by the conscious mind but your subconcious will pick up on it.

[thelazydogsback]

I have an old tribal rug (Turkish/Afghan?) that has a "evil eye" (but a good evil eye...) weaved into it in order to break the otherwise perfect symmetry of the design.

[fipar]

Agreed! Aesthetics is item g) in Knuth's list of example applications for 'Numbers that are "chosen at random"':

"A little bit of randomness makes computer-generated graphics and music seem more lively" (TAOCP, Vol 2 3rd Ed., Ch. 3, p 2)