Have you ever thought about your relationships with others? And, for that matter, with God? Do you have truly mature relationships, or are you just running in place, stuck as a relational preadolescent?
And let's not talk only about the easy stuff, like if you are growing. Let's consider things like why so many Christians have such a poor prayer life, or why most Christians who seldom touch their Bible. Why they are not growing. "What" is easy. "Why" is not.
Even though the why is far more difficult, it's also much more important.