Chris was an intense, stubborn and determined young man, much like his father. When he and his sister were young, their parents worked long hours at an aerospace business that Walt had started, which left little time to spend with the children, but brought a lot of money to the household, making Chris a child of some privilege. The real difficulty arose when Chris discovered the truth behind his father's divorce from his first marriage. Walt began a relationship with Billie (Chris' mother) and fathered Chris, while still being romantically involved with his first wife. Walt lived a double life, even fathering another child with his first wife despite having a life with Billie and his new family. When Chris found all of this out he considered his father to be a hypocrit, and never forgave him. (Krakauer, Chapter 12)
Chris McCandless was very angry toward his parents, but why isn't really clear. More of his anger is directed toward his father, and we know he condemns his father for the end of his first marriage, holding his father to an extremely high standard. Perhaps Chris and his father were too much alike or were too different to be able to get along. Many times, fathers will hold their sons to a high standard that the son doesn't feel he can ever achieve or live up to. Chris also felt his parents were tyrants, and he was resentful and bitter toward them. He was at an age where he wanted to prove himself, and his adventure into the wilderness seems to be a journey to find some truth about mankind. There's no doubt Chris was stubborn and determined and wanted to do things his way, which of course led to his death in the wild.