What quotes from Into the Wild show how Chris was disillusioned with society?

One good quote comes from the letter that Chris sent to
Ron Franz, encouraging the older man to experience new
things:

So
many people live within unhappy circumstances and yet will not take the initiative to
change their situation because they are conditioned to a life of...
conformity...

This quote
shows how Chris viewed the "safe" life that society expected from him and from others.
Chris wanted to challenge himself and his ideas, to pit himself against the world
regardless of what other people thought, and especially to avoid what he saw as the
endless trap of routine. By becoming a nomad, Chris forced himself to adapt to new
situations almost daily, and so escaped the daily grind that he saw as detrimental to
personal growth.

Another good quote comes from a letter
Chris wrote to his sister, explaining some of his passionate irritation with his
parents:

Since
they won't ever take me seriously... I'm going to completely knock them out of my life.
I'm going to divorce them as my parents once and for all...
(Krakauer,
Into the Wild,
Amazon.com)

This quote is
less about Chris philosophies and more about his dissatisfaction with the role that his
parents expected him to play. Chris fought against the ordinary lifestyle that his
parents enjoyed all his life, and with this letter, he explains that part of his intent
was to "punish" them for their constant nagging. By vanishing, Chris sent a message to
his parents that he was never going to play their intended role, but he also sent the
message that his path through life was not already written, that he was going to forge
his own path whatever the cost.