There were many driven characters on LOST. But what really motivated them?
POWER. Widmore was hellbent on reclaiming the island. In his banishment from the island, he amassed a great deal of wealth in order to "find" "his" island.
His son, Daniel, was looking for a different kind of power. One that could control time, as his lab rat experiments at Oxford would show was possible. But in his search for intellectual power, Daniel severely injured his assistant - - - and stopped his progress to attain power and its prestige.
Jack held the power of life and death over his severely injured patients. As a surgeon, his skill level would determine whether he would help or harm at patient. As with his father's demise for medical negligence, there is a fine line between being a miracle worker and a fraud.
CONTROL. Sawyer wanted to control his life after his parents deaths. He wanted to control his future for one event: revenge on Cooper. It gave him a narrow vision; and ironically turned himself into the person he hated most. He learned the skills of control by being a con man - - - looking deeply into the greed and desires of others, to manipulate them to his advantage.
Likewise, Ben wanted control of the island, not for the power but for the respect he never gathered from his own father. He banished Widmore so the Others would look up to him as their sole leader. Ben tightened his control by surrounding himself with new hires loyal to him.
However, Locke had the same want of being able to control his future as he received no respect from his father. But Locke failed because he never could formulate a workable plan where other people would follow his lead. And during the course of failure after failure, Locke became a bitter person.
Eloise was also a control freak. She knew of future events, and manipulated people like Desmond to get her chess pieces in place so she could have her own after death fantasy family life with a doting son and husband.
But those actions above were not the true motivations of people seeking power or control. The real motivation throughout the characters were their fear of loneliness. Widmore, Ben, Jack, Sawyer and Locke all battled against the stress of loneliness.
Kate was a flirty, gregarious child who got into trouble in order to connect with other people. She turned into a loner because she wanted to run away from commitment. But she found that made her even more alone.
Hurley always felt abandoned and alone when his father left him. Then his one best friend left him after he kept a secret from him. Hurley felt that he could trust no one with his new found wealth so he was crazed with the fear that his life would be one lonely road.
Desmond never fit in because he really did not want to try. He feared commitment so he took to the idea of being a loner. But after he met Penny, he wanted to free himself from the chains of loneliness but could not bear the confidence of being able to support Penny or win over her family.
In order to combat their lonely existence, the main characters found new hope when they were thrown together in an island survival story. None could make it on their own. "Live Together or Die Alone." They needed the friendship of each other in order to make their lives meaningful. They needed their friendships in order to move on with their lives. This is probably the clearest theme in the series.