How we cite our quotes: All quotations are from WALL-E.
Quote #4
CAPTAIN: Honestly, it's the one thing I get to do on this ship.
Even though the Captain's job is mostly useless, like Sigourney Weaver's in Galaxy Quest (appropriate, since in WALL-E she plays an actual computer) but he takes pride in his one duty: morning announcements. At least, he takes pride in it when he gets up early enough to do it.
Quote #5
[M-O leaves the green line to clean WALL-E's tracks.]
M-O's duty is to travel a green line and clean anything near it, but WALL-E's tracks are so dirty he abandons his post to follow them. Cleaning WALL-E becomes his new obsession.
Quote #6
AXIOM PASSENGERS: Yay, Captain! Captain, we're home, it's so beautiful.
CAPTAIN: No, it's nothing. I was pleased to do this. It's all about you people. It's not about me.
The Captain is fantasizing about doing something more than just sitting in his Captain's chair all day. Something little, like, oh, saving humanity. All in a day's work for our intrepid Captain (in his imagination).