A (hopefully) obviously satirical book - I couldn't put this down. It dealt with so many things I see regularly in "Christian" culture but took them to the extreme. The premise is the book is full of all the steps you need to take in order to put on the mantle of being a "perfect" Christian (or rather, a perfect example of what people think of when they think of worldly Christians).
Essentially you want to take every recommendation in this book and flip it around. To be fair, many ideas are good (for example, talking about the only way to properly train your kids is to homeschool), but the book demonstrates how they can be taken to the extreme (e.g. not only should you homeschool, but you should make it your mission to tell everyone else how their choices to send their kids to public school are the worst decision in life... etc).
I definitely noticed things in here that I've observed (and disliked) about certain other churches I've attended (like way too many programs customized for every unique whim). But then you run into things you notice about your own church (like "if the parking lot doesn't have attendants in bright yellow vests telling you where to go, they clearly don't care enough about your personal needs...")... oops - my church has parking attendants! Again, not every example in the book is bad, but it really makes you think.
Fortunately, the last short chapter makes it clear what the authors really think:
Wouldn't it be amazing if God simply loved the world so much that He sent His Son to be the perfect human on our behalf, who then suffered the penalty we should have suffered so that those who believe might be clothed in His righteousness and freed from the penalties of sin? If Jesus's righteousness were credited to us by faith, we could be assured of forgiveness and an eternity with our heavenly father.
That would be the most incredible expression of God's love ever conceived.
But then this whole book would then be pointless, because being a Christian wouldn't be about doing the right things and avoiding the wrong things. It would be about glorifying God in our lives because we adore and trust the One who loved us enough to give up everything for us.