Solving problems has been my life for the last three decades, so I know that solving the root cause or getting to “Why” is important. Figuring out why you are the way you are might not be nearly as important as you think in changing your habits though.
There are times when trying to get to the root cause is counter-productive. If the root cause of a particular issue has already been analyzed and a solution provided, you can skip that lengthy process and go right into applying the fix. In the IT world, we have entire knowledgebases dedicated to that process, because it dramatically speeds up a resolution when you can cross-reference previous issues that other clients have had and the solutions to those problems.
Let's take wanting to be more assertive for example.
Let's say we spend three weeks digging into why Susan is not assertive. We finally figure out that her father was very strict and so she learned growing up that being assertive was not effective, and in fact only got her punished. She was also constantly reminded to put others' needs first, so she feels guilty expressing her own needs.
Where does that leave us? Well, it might make Susan feel a little better to know why she is that way, but we are no closer to her actually being more assertive. Three weeks later, we are right back to the original question, how does Susan learn to express herself? Now, as a paid coach, that might be good for me because I got several extra sessions out of it trying to figure out why Susan isn't assertive in the first place, but it doesn't really help Susan become more confident in expressing herself.
The answer to that question is like wanting to be a better public speaker. It doesn't really matter why you are a lousy speaker. If you would like to be a better speaker, you will need to practice speaking and get feedback from a coach or a group like Toastmasters. We could spend weeks, months, or years analyzing why you are a poor public speaker, or you could use that time to start becoming a better speaker.
If Susan wants to be more assertive, then she will need to practice being assertive and get feedback to learn how to express her needs, regardless of why it is difficult for her at the moment. We get better at things by practicing them and getting feedback. Anything that you haven't practiced is going to be uncomfortable, sometimes very uncomfortable, which is why it helps to have someone guiding you.
That's why figuring out why you are not good at something isn't always productive. If you want to get better at anything, the quickest way to do that is to start practicing and have someone give you feedback. Before long, whatever you are practicing won't be quite as uncomfortable as it once was.