Sadly we live in a sinful world with sinners as friends. Its never too hard to offend even our closest companions. Daily we offend our God and Saviour and daily he forgives us. Churches are a breeding ground for sinful behaviour because Satan wants us so much to create instability and if he can prevent people from going to church then he will use any means possible to do that.
This is where any church must have good leadership, they must be able to deal with these things in a biblical way.
My own church has a Church Covenant, we are currently going through it in our morning worship services and it lays out the responsibilities of everyone who has covenanted together to serve the Lord together. I would ask that people who read this could look it up on Sermon Audio and have a listen. I hope its ok to leave the link. http://www.sermonaudio.com/search.asp?seriesOnly=true&currSection=sermonstopic&sourceid=salisbury&keyword=Church+Covenant&keyworddesc=Church+Covenant