To quote Henri Cartier-Bresson:

“Composition must be one of our constant preoccupations, but at the moment of shooting it can stem only from our intuition, for we are out to capture the fugitive moment, and all the interrelationships involved are on the move. In applying the Golden Rule, the only pair of compasses at the photographer's disposal is his own pair of eyes. [...]

If you start cutting or cropping a good photograph, it means death to the geometrically correct interplay of proportions. Besides, it very rarely happens that a photograph which was feebly composed can be saved by reconstruction of its composition under the darkroom's enlarger; the integrity of vision is no longer there. There is a lot of talk about camera angles; but the only valid angles in existence are the angles of the geometry of composition and not the ones fabricated by the photographer who falls flat on his stomach or performs other antics to procure his effects.” (“The Mind’s Eye” p34, 1999 Aperture ed.)