Maybe you've found something similar as you seek to grow in grace. You identify a project - controlling your overactive temper. And you go to work on your self-control. You start to identify triggers to your temper: the lousy driving of everyone on the road except you; disobedient children; the incompetence of a certain co-worker; your spouse not meeting your every expectation; etc. You try really hard in those moments to not lose your temper. But as you think about and pray for self-control, you begin to realize it's not just your temper. You don't have self-control when you're at the store with credit card in hand. The all-you-can-eat buffet is an occasion for unrestrained indulgence. High speed internet and an empty house are too much to resist.
Then by God's grace you begin to see that you don't just have a problem with self-control. You have a deeper problem of the heart. The reason that you can't control your temper is that (as Tedd Tripp once said in a counseling class) your kingdom isn't coming and your will isn't being done. In those situations you're saying that your way is better than God's. You are more important than he is. Your spending spree on credit is saying that God's provision for you isn't enough - you're bowing at the altar of gifts instead of the Giver. The over-indulgence of your physical appetites shows that you worship pleasure above God. What God has provided for you in Christ is not enough.
A little "self-improvement" project unearths some ugly stuff. Idolatry isn't pretty. But it's good you found it. When working on our house, I don't like finding new projects that need to be done, but in the long run it's better for the house and the people living in it. When you see red flags for projects/problems in your life (like controlling your temper), it's not self-improvement that you need; it's Jesus. Make no mistake; you have work to do in growing in grace, but if you try to do it on your own, you'll fail. You need his grace to do the painful work of digging deeper to find the heart problem behind the presenting symptoms. It hurts, but what a wonderful thing to find out that we have been worshiping self so that we can re-focus on our Savior, Jesus. In him we have a perfect righteousness; in him we have forgiveness of sins; in him we have everything we need for life and godliness. Why would we try to replace that with some lesser idol of our own making; why would we be satisfied with anything less?