The Torah states: וַיִּקַּח קֹרַח, “Korach…took”. (Num. 16,1) The Torah does not say what Korach took. Rashi says: לקח את עצמו, “He took himself…”. Rabbi Simcha Bunim expounds on this Rashi and says that Korach, indeed, was a bright man. He did have leadership qualities. His problem was that he did not wait until it was his time. He tried to usurp the power before he was asked.
In life, this happens too often. People try to assume power without being appointed. They may have leadership ability but leadership is not something that one takes upon himself. That is the act of dictators. Leaders have to be appointed or selected by the people.
There are times when no one wants to assume the authority to take care of a task that has to be done. In such a case it is desirable to volunteer. Yet, even in these circumstances one should not merely assume, since no one else stepped forward to undertake task that he could automatically step in without being officially accepted. Even in such cases he should volunteer but not merely assume the position.
People who take upon themselves responsibilities are not always appreciated by others.