Chris had fought with his father Walt's authority, mostly through passive-aggressive means, all through high-school. He felt that Walt was trying to restrict his mental growth and tie him to societal norms. Chris judged his father by his growing idealism, and refused to compromise those ideals.
When he graduated high-school, his sister Carine recalls that Walt gave Chris an expensive telescope at his graduation party, and Chris became very emotional:
"He was almost crying, fighting back the tears, telling Dad that even though they'd had their differences over the years, he was grateful for all the things Dad had done for him. Chris said how much he respected Dad for starting from nothing, working his way through college, busting his ass to support eight kids.
(Krakauer, Into the Wild, Amazon.com)
This moment of personal, emotional connection was rare for Chris, who tended to judge people and remain aloof. Although he did not repeat the performance, his friendly letters and postcards to his family (possibly sent as part of his desire to seem normal) show signs of love and interest. It is likely that Chris simply wanted to find himself before he matured enough to understand and accept Walt for the man he was; his reaction at the party showed that whatever else he felt, he was an emotional human being underneath, and that his connection to his parents was stronger than he knew or cared to admit.
After Chris had graduated high school his father, Walt, had a birthday party. At the party Chris gave his father a present that was a very expensive Questar telescope. Chris had been drinking some and was lit. He became emotional and nearly cried and told his dad that despite the problems through the years that he appreciated the things his father had done for him.
Chris actually had told his father that he was proud of him since his father had done everything from scratch to earn the living that he had eventually made for himself. (118)
This was unusual because he had been angry all the time with his father and clashed with him.