Toughest People to Love: How to Understand, Lead, and Love the Difficult People in Your Life--Including Yourself (2014, Eerdmans) is a useful book on understanding people that has a high Christology and a realistic anthropology.
DeGroat opened the book by discussing the challenges of the pastorate. He pointed out that 80% of new pastors quit within 5 years. As I often say to my friends, people are messy. He discusses the ineffective ways that we tend to lead and why they don't work before he moves on to discuss our deep relationality and how understanding that is the foundation of all good leadership.
One of the terms that DeGroat introduced was "beautiful complexity"--that we are not only sinful, but God's image bearers. We must be careful of simplifying people and trying to fit them into neat theological boxes.
Part 2 which deals with "leading and loving difficult people" is particularly beneficial. Often, I think Christians are leery of psychological categories, but they can be helpful in dealing with people. As his friend Johnny LaLonde said to him, "Labels are helpful when they broaden our ability to understand and empathize with a person. They're destructive when they confine us and cause us to see the person more narrowly." Having said that, DeGroat introduces the reader to terms such as personality disorders (borderline, narcissistic, obsessive-compulsive, and histrionic) as well as addiction and foolishness.
As he continued through the book, he explored the benefit of the dark night of the soul, a call to wholeness, and useful spiritual disciplines. I particularly liked discipline 4: "The freedom to break the rules." I have been offering this piece of wisdom to some rigid folks I know and it helps them to discover a freedom they did not know was available.
Whether you are a pastor or not, whether you are a leader or not, I would strongly recommend this book. I have already recommended it to my pastor and will no doubt recommend it again.