The three most influential factors in a horoscope are generally the Sun, Moon, and Ascendant. Thus they are a good place to begin analyzing a chart. While their weights may be nearly identical in terms of their influence, their functions are different.
The three most important elements in the fully-calculated birth-chart are the Rising-sign, Sun-sign and Moon-sign — in that order. We all know our Sun-sign, because we know our birth date. The Sun-sign is, in the opinion of many astrologers, second in importance to our Rising-sign, which relies on the precise time and location of our birth.
As many parts of speech as we have in language, they sometimes do not do justice to what is being described. And so it is in astrology. The word Mars "says" something that cannot compete with the aggressive, direct nature of its symbol. So, to facilitate memorization of each Sign, and to appreciate its archetype, we must appreciate what the symbol describes.