Why? Because!

“the aspects of things are so subtle and confused that they cannot in general be explained; and in the endeavor to explain some, we are sure to lose sight of others, while the natural over-estimate of the importance of those on which the attention is fixed causes us to exaggerate them . . . The best scholar is he whose eye is so keen as to see at once how the thing looks, and who need not therefore trouble himself with any reasons why it looks so”

(John Ruskin, The Elements of Drawing)