rivalries is another good descriptor to touch at another angle of what I was going for here, absolutely - it can be combatative, even abrasive, but in the sense of it working out there can be a weird respect in the end.

"and when you bite, you don't know when to stop" - this too is another great metaphor when that abrasive sense of play isn't instilled in enough folks... it almost feels like a vaccination of a kind, you know? if enough people or critters know how to bite (reasonably), harder for there to be genuine blood spilled.