The hazards of interviewing
"I know you believe you understand what you think I said, but I am not sure you realize that what you heard is not what I meant." -- Alan Greenspan

Not the most original quote I know, but he sums it up beautifully. The trouble with knowledge elicitation is that the knowledge elicitor is usually in the role of dumb chauffer that gets in the way of the person who really knows where they want to go... but can't drive.
Have you ever met the fearsome admin person that you know won't really understand your request but who insists on a full explanation before they'll pass you on to the person you really need to speak to? Have you then spent another 10 minutes undoing the garbled explanation of that that person got from their admin about why you're there?
10 years ago this was commonly called the "knowledge elicitation bottleneck" and the effects of interviewing were well known. Feels like its time to revive some of that. So, here's my own variant Greenspanism.

When you debrief you don't get the 'truth' as such but "an approximate articulation of what people are willing to say on what they think you want to hear, based on their imperfect recall of events they never fully understood."