Gee.. hard to narrow them down...
A CO telling my mother " This isn't Disneyland" when she was talking to him about a problem that he could have handled had he been so inclined.
My father, trying to explain the "present truth" theory to me " If you beleive that something is true based on all the facts that you are given, and you later find out that it is incorrect, you are not wrong for beleiving it. It was based on information that was valid at the time. You are only wrong if you refuse to change to the new understanding." I told him that was a crock.