When one connects the cross Numbers on a clock face, you get the following result:
8, 10, 12, 14, 16 and 18.
These numbers could be important because they form the basis of the formative years of a person's personal growth.
At common law, the age of 7 was deemed the age of reason. A person was expected to know the difference between right and wrong.
The age of 18 confirms adulthood. A person is emancipated from their parent's guardianship. They can join the military, make contracts, get married, etc.
How one what acts and behaves during the time between age 8 and 18 is important. What were the parental guidance? What were the environmental factors? What were the support mechanisms? Did the person learn values, goals and ethics? Did he or she fall in the wrong crowd?
Look at the people devoid of parental love and attention:
Locke.
Ben.
Sawyer (after his parents were killed).
Look at people who only had the attention of one parent:
Hurley.
Kate.
Shannon.
Walt.
Claire.
Jin.
Look at people who had a "normal" upbringing:
Jack.
Sun.
Sayid.
In the "normal" group, Jack had the upper middle class upbringing which led him to become a highly respected surgeon. He was smart, encouraged, had the means and opportunity to get a large slice of the American Dream. But in the end, was he a happy person?
Sun came from a very wealthy family. She was repressed by class status and her Korean culture. The only way she could get attention and feel independent was to rebel against her father in the worst possible way: by marrying a poor man. But even that goal did not make her a happy person.
Sayid grew up in a tight family setting in Iraq. His household was ruled by a strict father and a demanding culture. Sayid did what he had to do - - - such as butchering an animal his older brother could not do - - - which gave himself value to the group. And that need to be valuable in a group was the anchor that dragged his personal ambition and happiness down.
In many ways, the characters brought up by one parent have two common traits: loneliness and selfishness. Hurley was raised by his strict mother after his father left. She was religious and pushy, especially about his social life. That caused Hurley to eat to repress his social life. As a result, his mother enabled him to become a shy, quiet, dependent child who would never want to leave the artificial womb of her home. It is selfish to stay with a parent when, with any personal drive, you should be on your own. Claire had a similar relationship with her mother. Her mother wanted her to settle on a normal path, but Claire had a wild streak. They would fight over trivial matters. The last argument led to her mother's severe and fatal injuries.
You can add bitterness to characters like Kate and Walt. They were given a relatively carefree life, their needs being met by their mothers, but they were not very grateful. Each would act up in a controlled tantrum for attention. Then they were upset when things did not go their way, not understanding that it is the effort you have to put in yourself to get the result you want.
The characters who lost their parents early in the childhood, Ben, Locke and Sawyer, all had one driving trait: criminality. Their moral compasses did not have the bearings that parents instill in their children. Ben was beaten down daily by his alcoholic father who blamed Ben for his own shortcomings and lousy life. Locke's known abandonment was reinforced like a knife blade in his back each day he was in a foster home. Sawyer could only think of revenge after his father committed murder-suicide because of a con-man's trick on the family. Each would cross paths in the criminal world and go with its flow, including Locke - - - in seeking a "family" would have been fine living in a drug selling commune if they would accept him.
They say there is good and bad in everyone. What dominates a person's adulthood comes from what happens when a child is 8 to 18 years old. Each of LOST's main characters personalities were crystallized by events that happened in their childhoods.