Why did Gustave Flaubert revise his writing so carefully?

Gustave Flaubert revised his writing with extreme care because he was driven by an uncompromising pursuit of artistic perfection and beauty. His primary goal was to achieve a style that was simultaneously as rhythmical as verse and as precise as the language of science.12

Flaubert believed that a writer must track down le seul mot juste—the unique right word—to convey a thought with absolute precision, often stating that synonyms did not exist. Beyond mere accuracy, he meticulously crafted the cadence and harmony of his prose to appeal to the reader's subconscious mind, much like music, ensuring a more penetrating effect than the literal meaning of the words.1

This dedication to his craft was a source of great personal anguish, as he constantly revisited his subjects, often rewriting works over many years because he was rarely satisfied with his initial results. Ultimately, he sought a level of objectivity where the author remained present everywhere in the work but visible nowhere.12