Church is meant to be a refuge for us all, because none of us are perfect. So, if you put a bunch of imperfect people in one setting, and they start to work closely together, problems will inevitably arise. Churches also attract a certain proportion of people on the margins. They are unable to hold a job, for one reason or another. So, in addition to having a place to worship, they also need a place to hang their hats, so to speak. They then become over involved in the workings of a parish.
However, most of the people you'll encounter in a Christian setting are absolutely delightful. A minority may also be deeply disturbed, which is something that caught me off guard. By this I mean they may suffer from a personality disorder, such as malignant narcissism. This isn't always apparent in the beginning though. Someone returning to their faith, or someone new to a particular place of worship, is probably most at risk of being ensnared in an unhealthy dynamic.
Again, the best way to avoid being caught up in a bad situation at church, especially if you have children, is to attend with your eyes open. Go there to pray. Stay away from projects and politics. Not getting too involved is your best insurance against a bad experience at church.