If we do what they ask then our task is relatively easy: just administer and then explain the results from one of the many available vocational interest tests. And the client will probably be relieved of their burden of choice. Here's one view of why this should be, from Renata Salecl, who is currently Centennial Professor in the department of law at the London School of Economics and Senior Researcher in the Institute of Criminology at the Faculty of Law in Ljubljana, Slovenia.
Who Am I For Myself? Anxiety & The Tyranny of Choice [first third part only]
But don't we want the client to take an active, creative rôle, with some understanding of the constraints within which they must operate?