Denominations are actually good for unity I believe. As the saying goes, fences make good neighbors. It is true they tend to become symbols of exclusion, but I believe most of them are the result of honest and sincere people trying to find the truest path they can find.
Recently a group of people left our church over a disagreement over a doctrinal issue. To them the issue warranted parting ways. And so it goes. SI herself is a community that attracts separatists who are dissatisfied with their local churches. Every week we critique others, placing them outside of our own spheres, identifying ourselves as different from their faults. Perhaps the only thing that keeps SI from becoming a denomination is that she is not an actual church. If she was, it is almost certain within a generation that a coda of accepted doctrine and behavior would be instituted and she would be routinized into a denomination of sincere disciples.
While I understand the weariness we have with factions and partisan spirit, I personally think the glory of achieving an earthly church without denominations is beyond the reach of this dispensation. Once we no longer have to look through a glass darkly, and can see God as he truly is, then I believe we will have no denominations.
A few years ago, several families within my larger family decided to try living together. It has been quite a challenge not simply because they are selfish, but because their values are slightly different. Some value hard work as the highest life principle, others value family time as the highest priority. Each thinks the other needs to see things their way. Often their differences give rise to deeply felt misunderstandings and hurts. In the end they stay together out of love for one another, but it has been an instructive experiment to say the least.
So, while we love our larger family, we find it more manageable to live together in smaller family units. There are fewer heads of the household, operating as both high priest, and material provider. There are fewer debates over what is more important among such faultless but often irreconcilable virtues such as frugality, raising children, saving money, ministering to the community, achieving career goals, preparing for Christ' return, preparing for retirement ect. Individual households can more readily find agreement on these specific points.
So we have own households that we are comfortable with, our out of town relatives we love and like to visit on holidays...and those bad seed relatives whose existence we would rather forget altogether. We may be one tribe of Abraham, but we raise our families in separate tents.
:-)
MC