I've played on teams. Didn't trust everyone on the team. Yes, I know you're supposed to be able to trust your teammates but that isn't always the case. Not in real life anyway.

Teams still have internal struggles that include jealousy, hostile competition within the group, people still try to outshine their teammates, some try to position themselves as the "go-to" in the team. Teammates can be influenced, and not always for the good, by other teammates. Someone is always hot-dogging/showboating.

Just explaining why I chose to say it is more painful to be stabbed in the back by someone you trust instead of by an enemy or teammate.