It's an interesting and inadequately addressed subject, considering how pervasive territorial behavior is among humans. I engage in territorial behavior. You do. Everyone who has enough consciousness to perceive personal space and who grasps the concept of personal property engages in territorial behavior. However, most of us, including myself, invariably will deny engaging in such behavior if called on it in reference to a specific incident. We will claim that territorial behavior is for animals, that we are civilized....and then go on to be thoroughly outraged when the boundaries of our territory are breached.
Social mores, niceness, sociable behavior in general, are the counterpoint to territoriality. There cannot be niceness/good behavior when territory is disregarded, and tactful/polite behavior is what makes navigating territory not only manageable, but worthwhile and rewarding.