And Korach took [a bold step] and they rose up before Moses (Num. 16:1-2)
The Mishna states in Tractate Avot (5:17): "Which is a controversy that is not for the sake of Heaven? The controversy of Korach and all his faction." The Mishna specifically avoids calling it a controversy between Korach and Moses, because even within Korach's group of 250 followers there was dissention, each one vying with the others for honor and glory. Indeed, this was a sure sign that their argument was not for the sake of Heaven. (Ye'arot Devash)
A person who is broadminded will not respond to taunts, as he is mature enough to disregard them. By contrast, a person who is narrow-minded is unable to tolerate anything that goes against his will, and becomes immediately angered like a young child. In Chasidic terms, unity is derived from "broadness of the intellect"; controversy results from "smallness of intellect." (Maamarei Admor HaZakein)