Words are powerful. Even more so are great questions.
If this weren't the case no one should be able to make a living interviewing people, whether it be a therapist, coach, or talk show host.
I believe that self-awareness is essential before choosing to do anything. Without understanding your own desires, strengths, passions, fears etc... how do you hope to make a decision that will make tomorrow better than today?
In my journey of introspection I've learned to ask myself "why" repeatedly. It seemed to be the fastest way to grill down to the first principles of any desire or goal. It's a common technique used by people whose work I admire like Ricardo Semler and Simon Sinek.
The basic form of the exercise is to ask "why" three times to any statement or fact you may have. "I love powerlifting. Why? Because I love the constant training process of getting stronger incrementally. Why? Because I think constant improvement in health is essential to be an optimal human being. Why? Life is a full system. Wealth and wisdom are nothing without health." This was a process that helped distill down to the roots of my passion to understand it was overall human development.
However, asking "why" for everything didn't always work out. At times, the search for clarity through examination resulted in increased anxiety. It made me realize it may have been rooted in the question I've been asking myself.
If I failed to complete a task or meet a goal, asking myself "Why" and digging down made it apparent of how idiotic I was to have made the mistake in the first place or lamenting at my sheer laziness and procrastination.
"Why" wasn't working for me here. But, "What" seemed to work better. Asking "what I could have done not to repeat the mistake" or "what I can do to improve for the next time" was a way of creating an action for the future through analyzing the past. This was constructive to continuous improvement.
So now, when I conduct my end of day reflection in my daily journal I end with a series of "What" questions:
What did I learn today?
What did I create today?
What could you improve for tomorrow?
What makes you better today than yesterday?
"Why" focused on finding the underlying meaning for the action or desire and that made me look into analysis of facts from the past. This was of value for determining goals because it allowed me to uncover the intrinsic driver that could be used to motivate my pursuit. But alas, there really isn't a "one question to rule em all" and affirms the teaching that questions become great when used in the proper context.
My learning has been thus:
In analyzing the results of the past, ask "what"
In analyzing a goal for the future, ask "why"