Good relationships are essential, but teams also have to accomplish a very specific vision and mission. They have to perform. To do that requires not only values that drive the correctly aligned behaviors that drive the business, but also values that prevent behaviors that limit or hurt the business. Add accountability practices to that and you have a jet engine for a team.
A team is not a "group of people." A team is a group of people who have a shared purpose or goal. The shared purpose or goal brings them together to perform to reach that goal. And to reach the goal, the team is going to have to look and operate in a certain way. The team‘s values and value-driven behaviors are going to make that goal a reality.