Very interesting thread jcwren
Several years ago when I was coding, I took the attitude for the most part, that "What a mistake in MY code ??" "No Way".
After getting older, but not necessarily wiser, I've since learned what works best for me is to tell the user to "show me what it is doing". This way, you're not admitting anything, nor are you denying anything. You shouldn't be frowned upon for not wanting to be helpful as you're actively investigating the problem with the user. Quite often I've found either they are trying to do something that was not intended, stupid user tricks, or they actually did find a bug. What ever the result, I either patiently explain to them the error of their ways (while silently having other thoughts) or I ask them to give me a few minutes to resolve the problem. YMMV...