I have noticed that there's something with shoes. Jack tells Kate if she is going in the jungle with him to find the front of the plane (Pilot, part 1), she needs better shoes. She finds them on a dead man, nice, sturdy hiking shoes. Then, when it focuses on Locke (Walkabout), he is shown on the beach without shoes on, but later has a good pair.
A couple of themes that comes to mind is preparedness and a sense of new beginning. All of the Lostees were thrust into a situation they had never been in before, and most were very much not prepared for it. But, by receiving help from those who would not be part of this new journey, some Lostees found themselves more prepared to face what was coming on the island, physically (hence the shoes), but more important, emotionally and spiritually.
Kate put on the shoes, and had a new beginning. She was ready to be a different person, one she needed to be to survive and help others do the same. Locke, who before had no reason to wear shoes because he was in a wheel chair, found himself with the opportunity to start over, and he would new a new pair of shoes. Both found some good rugged shoes (as did others, I'm sure), which gives the impression that they both were ready to fill those shoes, and they did a good job of it.
Others, like Shannon who is seen much of the time in flip-flops, are not supported by their shoes, and others have to do it for them. Shannon really does not do much to help herself, like getting Charlie to catch a fish for her, or she wastes time tanning or moaning, while others need help. That brings a question to mind-If you were on the island, what kind of shoes would you choose to wear?
Then, there's Christian, who Jacks sees from time to time (quite often in his turmoil in White Rabbit). It looks like he's got some pumps on, some white sneakers. There is an episode at some point where Jack says he does not have a pair of nice shoes for his father, so has to give him a pair of his white sneakers (at the funeral, nobody would see his feet anyway). The name of the episode where Jack sees Christian quite often is in White Rabbit. White Rabbit, white sneakers. Hmm.
So, Christian is Jack's white rabbit on the island, and of course in reference to Alice in Wonderland's white rabbit, Jack is suppose to follow this white rabbit. The purpose? To understand that the people need a leader, and he needs to fill those shoes. He was trying to do too much, trying to save everyone, but realized that he could not do it all. With the flashbacks, Christian told his son not to be a hero, because he would fail, and couldn't cope with his failure. But by following the white rabbit, he goes on an emotional journey needed to become the leader the people need, throughout the whole series.
