This might be only a me thing, but, here goes.
When I am working out a situation in person or on the phone with a vendor—a rental car agency, for example—and they lay out what the situation is, I like to explain it back to them and have them answer yes or no to make sure I understand. Seems easy to me: "OK, let me play it back to you to see if I understand—this, then this, then that. Do I have that straight?" And they reply either yes that's right, or no this other thing instead. Then I play it back again with the correction to make sure I have it right, until we are both on the same page. Sounds logical and even easy, to me, anyway.
Most of the time it works fine, but every once in a while, you get someone who simply can't do this, or who don't understand what I'm trying to do. I say, "Let me play this back to see whether I understand ...", I get one point into it, then they take over replaying part of the spiel and start introducing new information that didn't come out before. Then I say, "OK, let me see if I understand that ...", and I get one point into that, and then they say, no no no no you're not listening to me, and then start the whole thing all over again, perhaps with points they had made before now missing. Meanwhile, I'm going crazy because they're going all over the place and scrambling my understanding of the situation. It's maddening.
It was even worse today because when I started explaining what I thought I understood, the rental car agent started talking over me, I was talking over her to ask her please, just listen to me and let me explain it to you so I understand, and she did not pause for even a beat from her obviously scripted spiel. As it turns out, when I finally did get through to her with my understanding of it, she had completely misunderstood both the return date and the return venue for the car. I imagine she was getting flustered and was retreating into the known spiel to anchor herself which, fine, I suppose I get that, but that doesn't help me understand the deal we're trying to work out. It had basically descended into a battle of wills.
Some people apparently cannot effectively process changes on their feet. Everything they deal with has to fit neatly into whatever the spiel they learned is, or they withdraw or shut down. Those people should not have jobs facing customers.