If you want to avoid being manipulated, keeping your motivational structure secret is a good idea.

FWIW, the Church of the SubGenius advocates the "Nameless Mission. To name it is to doom it." I have found this a useful concept when there's something driving me and I've yet to find its true name, but like its results so far. I also gave the concept to a friend who's sick of their field (they've basically won that game) and about to change their entire career, isn't quite sure what to pursue next but is accumulating new hobbies of great interest.