Po-tae-to, Po-tat-o: From a Seedling to ...........

Why do empires form? Is it due to the thirst for expansion? Urge for control? Domestic Issues? One Elitist? The answer: all of the above. Human desires take over and whilst power and wealth has its ups, it sure has its downs as well.
Rome: a paragon of how wealth and power lead to corruption but hey, it led to an empire. At the beginning, the Gracchi brothers attempted to rule with iron fists when it came to land distribution. Unfortunately, as the republic grew, different social classes felt as if they deserved more land. This led to heightened social tensions and a civil war. The rulers who controlled the Roman "ground", I suppose that's what it shall be called for now, only fueled the anger of the people and made things worse. Then Julius Caesar rose from the ground and became immensely popular. He became "that guy". His politics were headed in the way of a centralized government and after him, that's the road the Romans took.
China: Internal conflicts led to the unification of China and therefore those conflicts led to an empire that ruled over the unified China. During the Period of Warring States multiple dynasties tried to unify China again and become rulers over a vast piece of land. Economic development also led to the unification and "empirzation"of China as the economic prospered there was a need for rules and regulations. Whenever there is a need for some sort of authority, usually someone steps up the plate and takes control leading to a centralized government.
India: After Alexander the "Great" left an empty void with no one to take his place in India, different people, who believed that they were the ones who could bring change, attempted to unify all of India. In fact, Alexander's absence spurred the formation of empires. The unification of India, economic development, and social distinctions all were factors in the process of the creation of the Indian empire(s).