How would one elicit knowledge from experts who cannot say what they mean or mean what they say?

What does one say or do when the expert says, $$Look$,$ I work with shades of gray reasoning. I simply look at the problem and decide. Don$$t ask me why or how.$$

How does one set up the problem domain when one has only a general idea of what it should be$?$

What does one do if the relationship with the domain expert turns out to be difficult?

What happens if the expert dislikes the knowledge developer?

How to handle above issues?