The Merriam Webster dictionary defines Influence as the power to change or affect someone or something : the power to cause changes without directly producing them to happen.
In every sphere of life, influence is exercised. Often times, influence may not clearly be seen since it's not an attribute or trait that is commonly exercised by the average person. Most folks may find themselves under the influence of people or things and not know that they are under influence. Others may have influence on other people and may probably not know that what they are exercising is influence.
Influence is that attribute every leader seeks, without it a leader's voice is powerless without any potency or power. The inability to get people doing exactly what they are supposed to do or asked to do some times could be a function of the fact that, the leader giving out such instructions may not be influential on his people that much. People don't just obey any leader because, they are leaders, People are moved by the influence exercised by a leader. That attribute that gives a leader an upper hand over the affairs of his followers.