The shor represented full-fledged idolatry. In the Altar he saw the shape of an ox, implying the heavy burden and awesome responsibility of Torah leadership. Only a leader who fears the results of error, who places before himself the overwhelming responsibility of his position, is qualified to lead. This is probably true in every area of endeavor. One who does not fear the result of his error should not be in a position of leadership.
True success is achieved when one has the ability to acknowledge and confront error.
And Aharon was silent. Aharon silently accepted Hashem's decree only after Moshe consoled him by telling him of the enormous kiddush Hashem, sanctification of Hashem's Name, which Nadav and Avihu had effected. Aharon's response to the tragic deaths of his two eldest sons serves as a paradigm for those who confront tragedy. He was silent, accepting the decree. In fact, we find that Hashem singled out Aharon, speaking directly to him about the laws concerning Kohanim serving in the Mikdash after having imbibed intoxicants.