Once in a while bloggers will bring up the subject of why Ben can't or won't leave the island, especially in light of the fact that he was sick and needed treatment. I think that this is a very interesting question, also since Ben doesn't seem to have any friends on the island -- through his own fault or that of his circumstances. He's pretty much a man alone in a crowd which he expressed with his quote from "Of Mice And Men" to Sawyer.
We know that Ben was not too happy as a child living on the island with his dad, and as an adult he seemed to be as disgusted with the DIs as his father was, albeit maybe for different reasons. Assuming that people actually can come and go from the island, as we witnessed Richard doing, why doesn't Ben leave? Is it because on the island he is a very important big fish in a little pond, and back in the world he would be a nobody in a big pond? Or could Jacob possibly kill Ben from afar, like he supposedly healed Juliet's sister, if he jumped on the sub and ditched his island responsibilities?
I suppose that there is the chance that Ben really did come to love the special island where fate (or Mrs. Hawking?) placed him as a child. Or he might have grown a close sympathy for the island's indigenous people who love the island, and he wants to help them to keep it sacred. Worst case scenario, he really wants to leave but he is Jacob's (or Hawking's) island puppet and has no choice at all. That explanation might also reveal why he has no sympathy for others like Juliet who are trapped there-- because if he can't leave, why should they be able to? This is another case where I hope that we can look back and see the light about this mystery before the end of the series comes.