In his book Christian Living Beyond Belief, Cliff McManis pointedly argues why your spiritual maturity (or lack of) affect your local church:
Here is a basic, yet huge principle of true biblical church growth that is frequently overlooked: corporate church growth is contingent upon and augmented by individual and personal growth. For the body at large to grow, first the individual members need to grow. Tiny cells are the building blocks that enable the whole human body to grow as a unit. So it is in the church. If we want strong, growing churches then the emphasis needs to be on cultivating and encouraging spiritually healthy, mature individual Christians. We need to focus on depth, not breadth. We need to go deeper before we go wider. Many churches have it backwards. They believe individual growth flows from corporate growth, when just the opposite is true – corporate growth is a natural spiritual byproduct of personal Christian growth [(The Woodlands: The Kress Christian Publications, 2006), 10].
Unfortunately, what seems so simple, logical, and biblical is such a foreign concept to many professing believers. People find easier to criticize their churches than honestly criticize their own spiritual condition.