why do mccandless left on this personal and self-destructive odyssey?

To McCandless and many others of his ilk, the wilderness has a very specific allure. McCandless sees the wilderness as a purer state, a place free of the evils of modern society, where someone like him can find out what he is really made of, live by his own rules, and be completely free. And this is not just naïveté; McCandless's journal entries show that he does find some answers, some keys to living the way he wants to live. Like his mentor Thoreau Chris fantasized about living deliberately, he wanted to "suck the marrow" out of life.