Maybe instead of asking ourselves what we want to DO for a living, we ought to ask what we want to BE. That's a much more pointed question and could get us at the "right answer" quicker than expecting us to know what we want to DO in choosing a suitable career path.
Doing is activity; being is a state of identity. The dictionary states that "being is the nature or essence of a person." We can't possibly know what we want to do before we understand who we are and what we want to be. Optimally, we want to align our choice with our nature or essence. That correlation must feel like home to us. Could it be that in questioning ourselves in this manner, we would get closer to the truth of who we are and what we are consciously accepting as our destiny?
Asking the question of being inserts the authenticity of the soul's purpose, while the doing could easily involve more elements of our ego, which we know is highly influenced by worldly factors that have little to do with who we are.
We already know that we are not taught much from either parents or teachers on how to go about an internal reflection of heart and soul on the matter of career. That is up to us as individuals to seek out and choose. It is a responsibility that we can neither deny or afford to ignore.