The following words are quoted by Tim Chester and Steve Timmis in Everyday Church: Gospel Communities on Mission. I think Bonhoeffer hits at the heart of why many people find church community disappointing at times, and at the location of the solution.
“Those who dream of [an] idealized community,” warns Dietrich Bonhoeffer, “demand that it be fulfilled by God, by others, and by themselves. They enter the community of Christians with their demands, set up their own law, and judge one another and even God accordingly.”
[We] can never live by our own words and deeds, but only by that one Word and deed that really binds us together, the forgiveness of sins in Jesus Christ. . . . Christian community is not an ideal we have to realize, but rather a reality created by God in Christ in which we may participate. The more clearly we learn to recognize that the ground and strength and promise of all our community is in Jesus Christ alone, the more calmly we will learn to think about our community and pray and hope for it.