Over the course of the novel, one of the main storylines is the way that Jonas changes. He goes from being someone who completely accepts the way his society is to someone who is totally willing to (essentially) destroy it.
At the beginning of the book, Jonas has no problems with his society. He has no problems obeying the rules. His only worry is whether he will be assigned a good job.
By the end of the novel, he is thinking for himself. He has decided that the Sameness he grew up with is completely unacceptable. He is willing to go Elsewhere and release all his "memories" back into the community even though this will surely destroy it.