Quote 1
"You know that I have the greatest possible enthusiasm for this mission." (24.43)
Plans and goals tend to be seen as good things in 2001. The aliens' plans lead to the emergence of the humans we are today, and ultimately move us up the evolutionary ladder. Hal's enthusiasm for the mission, his single-minded devotion to the hopes and plans of Discovery, are a bit of a contrast. They don't end up leading anywhere good. (Trust aliens, not robots.)
Quote 2
"I don't want to insist on it, Dave, but I am incapable of making an error." (24.23)
Hal is supposed to be incapable of making an error. Alas, he is full of them. This is why he's so much fun; all the other characters are professional and qualified and strong and skillful. Hal, with his neurotic burping brain, is much more sympathetic.