[dmlittle]

I remember hearing about a CEO that was unable to get any feedback from the board of directors until the phrasing of the question asked shifted from criticism/feedback to advice.

People are worried of giving criticism because you're effectively asking them to rate/evaluate your performance. However, when you ask for advice you're either asking what the other person would do in your shoes or you give them an opportunity to boast about their knowledge. While the end goal is the same, at a psychological level, the perceived reason for the question is different.