Casting such a broad net with the word "doubt" suggests that all questions are argumentative. But in fact, almost none of the questions listed here are necessarily expressions of doubt or the basis for an argument. They are expressions of seeking understanding, which is a designer's job.
A designer who is not a question machine can only ever put lipstick on your product, not really make it better.
A designer who is not a question machine can only ever put lipstick on your product, not really make it better.