Mr. Knew-It-Before-You-Did.
Smug, dismissive, confrontational. Insulted by his junior status: I'm too good for my assignments. Derisive of others' efforts.
Assigned to you as your protege, for the duration.
Snickering: "Why don't you just use Perforce?"
Serious: "Because I wouldn't be able to retrieve anything from the CVS repository."