The Designer Usually Works with a Team
The development of a video game generally involves a team of individuals with diverse skills and interests. In the author's mind, the key to successful cooperation is a mutual "love" for the game they are producing. His take seems to be that you should love it, or learn to love it - which is not at all helpful.
A more practical concern is the differences that arise when the team attempts to work together toward a common goal: they may differ on their vision of what the goal should be, or may differ on the best way to get there.
He stumbles on this one too, some comments on ground rules, shared versus individual responsibilities, fostering good communication, etc. There are definitely better sources on teambuilding and personnel management, so I'll skip the rest of this section.