Quote 67
This is because I do not always do what I am told.
And this is because when people tell you what to do it is usually confusing and does not make sense. (59.2-3)
Here's an interesting juxtaposition: Christopher feels confined (we might even say imprisoned) by being unable to understand directions. This allows him to justify not following said directions, leaving him free to do whatever the heck he wants.
Quote 68
Then, when I've got a degree in Maths, or Physics, or Maths and Physics, I will be able to get a job and earn lots of money and I will be able to pay someone who can look after me and cook my meals and wash my clothes [...] (71.8)
Christopher fantasizes about getting a job, and the freedom that comes from having money of his own. He would use the money to hire someone to help him live on his own, without needing his father to take care of him. Freedom begets freedom.
Quote 69
I used to have lots of Behavioural Problems, but I don't have so many now because I'm more grown up and I can take decisions for myself and do things on my own like going out of the house and buying things at the shop at the end of the road. (73.1)
This is the first time we hear about Christopher's behavior having generally improved over time. A few other times, he mentions specific lessons he's learned (about not hitting people, for one thing), but this comment is interesting because it represents his having gained freedom by restraining himself from actions he's learned are unacceptable.