Church is relationships.
A healthy church is just a healthy collection of relationships. If the people in a church don't have healthy relationships with one another, then they aren't really a church but a collection of lone-ranger Christians. If you think you are in an unhealthy church, it is more than likely that the relationships in the church aren't healthy. Sometimes a church can be unhealthy for other reasons, but I have yet to see a case of that. We have severe relationshp problems in our churches.
And it starts with the leadership.
A healthy leadership is a group of people who have healthy relationships with one another. If they don't have healthy relationships, then it will be just a matter of time before the church falls apart. If they do have healthy relationships, it will be just a matter of time before the church is healthy. Obviously, the fact that they are focused on the will of God and living out the teachings of Scripture are prerequisites. But I do believe most church leaders try to do that. It is in the area of healthy relationships that I see a lot of failures.
Watch out for the potholes.