The problem with using the analogy of the Major Dramatic Question is that the question "Will Hamlet--?" isn't answered from within, it's answered mostly based on clues from the play, from the plot, which guide it in a certain direction. This may be a good way for Nervous to concentrate her efforts: by looking at specific instances from her own past, problems she has solved, ways that she has dealt with things. Simply "soul searching" makes a great bumper-sticker, but it can lead to some radical wish-fulfillment dead-ends. If led unchecked, it could provide answers like "Hamlet really wants to explore the universe". It isn't enough to simply look within, a big part of it consists of looking back and possibly even of talking to other people as a mirror for looking at yourself.Of course, we're dealing with an analogy here, so the correspondence won't be one-to-one, but the point he is making is true: the further along in the play you are (i.e., the older you are), the easier it is to recognize the Major Dramatic Question.
However, without going into a major play analysis geek out, I would also point out that the MD? arises when the protagonist first commits to a course of action, which we call the Moment of Engagement. This is the moment when the protagonist takes the first step along the road that is the play. In Hamlet, it occurs in Act I Sc 5, when Hamlet speaks to the Ghost of his father, who tells Hamlet he must "Revenge his foul and most unnatural murder," to which Hamlet responds, " Now to my word; It is 'Adieu, adieu! remember me.'I have sworn 't." At that moment, Hamlet commits to a course of action, and the audience wants to know whether Hamlet will kill Claudius. In other words, while the MD? is answered at the end of the play, it starts very early in the play. Had Hamlet said to the Ghost, like Dickens' Scrooge, "
All of which is to say: you don't have to know how the play ends to find your "why." It is a commitment to a specific course of action.
But I would also agree with my waltzing friend's point that your "why" doesn't come wholly out of one's inner self. By all means, look back on your past experiences to find out the characteristics of those that gave the greatest fulfillment. And be specific. If you really enjoyed working on a particular show, what made it fulfilling? Were there certain rehearsals that were satisfying -- what made them so? Was it working with a certain individual? What is it about them that made it fulfilling? Was it what the play had to say? And don't just confine yourself to theatre experiences. What experiences in school, on the job, in a volunteer organization did you find fulfilling, and why? You're looking to see if there is a common thread, something that can be applied to a variety of situations.
The goal is to fill your life with as many things as possible that you find fulfilling.
That's why it is a good idea to make sure you don't confuse your "why" with your "what." If you make them the same ("my why is to do theatre, because doing theatre is what gets me out of bed in the morning"), then you have only a single option. And that means you will spend much of your time frustrated and unfulfilled, define your non-theatre work in a way that is unfulfilling ("my day job is the lousy thing I have to do to put a roof over my head so I can do theatre"), and miss a lot of opportunities that will be fulfilling. Maybe even more fulfilling than theatre,
As far as "wish-fulfillment dead ends," there is nothing about this process that guarantees success. After all, Hamlet might have been killed before he revenged his father's murder. But joy comes from trying to accomplish something, and being aware of the experience as it occurs.