A current Slate article explores the satisfying nature of symmetry. Here's a brief excerpt:
Why is architectural symmetry so satisfying? As Leonardo da Vinci's famous drawing demonstrated, it reflects the human body, which has a right side and a left, a back and a front, the navel in the very center. Du Sautoy writes that the human mind seems constantly drawn to anything that embodies some aspect of symmetry. He observes that "[a]rtwork, architecture and music from ancient times to the present day play on the idea of things which mirror each other in interesting ways." When we walk around a Baroque church, we experience many changing views, but when we walk down the main aisle—the line along which the mirror images of the left and right sides meet—we know that we are in a special relationship to our surroundings. And when we stand below the dome of the crossing, at the confluence of four symmetries, we know we have arrived.
On the other hand:
All exemplary Modernist buildings celebrated asymmetry: The wings of Walter Gropius' Bauhaus shoot off in different directions; the columns of Mies van der Rohe's Barcelona Pavilion are symmetrical, but you can hardly tell, thanks to the randomly spaced walls; nothing in Frank Lloyd Wright's pinwheeling Fallingwater mirrors anything else; and Le Corbusier's Ronchamps dispenses with traditional church geometry altogether.
The article offers a nice review of the symmetrical / asymmetrical perspectives.