I personally prefer earnest over disingenuous. There are fewer opportunities to misunderstand. A question by it's nature isn't aggressive. The words "should" a

I personally prefer earnest over disingenuous. There are fewer opportunities to misunderstand. A question by it's nature isn't aggressive. The words "should" and "we" are the real cancers IMO, as in "we should have done..." I think your example of have you thought about, vs. Why did you is potentially better but I personally don't have an issue answering either question or feel attacked in either case. I would on the other hand be concerned about working with someone immature enough to read in so far to perfectly innocuous curiosity.