Do you ever have conversations with people, in which they clearly have no idea what you are talking about?

All the time. Especially when Christians are telling me what Jews believe.

One particular person comes to mine but I view her more as an acquaintance than a friend because, frankly, I can’t be friends with someone that I can’t have an intelligent conversation with.
She is an expert on everything. Her husband had high cholesterol so she proceeded to lecture us on cholesterol.
“You have your bad cholesterol which is HDL, then you have your good cholesterol, which is LOL.” I had to choke myself to keep from LOLing!

I have an entrapped ulnar nerve. It originates in my elbow. She saw my long wrist brace and asked what it was for. I told her it was for an entrapped ulnar nerve.
She said, “No, it isn’t. It’s carpel tunnel syndrome.” And proceeded to shower me with her astounding knowledge of carpel tunnel. “You have carpels all over your body. Everywhere. They’re in your hands, your feet, your elbows, in the back of your legs, everywhere! And what happens is….” honestly, I can’t even remember what said said the cause was.
I said, “Um, Kathy. Carpel bones are the bones in your wrist.”
She just told me I didn’t know what I was talking about, and just went on blathering. So…

And I have a sister who is much more focused on what she has to say than listening to me, so yeah, she’ll interrupt in the middle of something I’m saying and take off in another direction.

Sure. For people like that, there is no listening, just waiting to talk.

Lord. The person I mentioned above asked to come over to borrow our printer because her’s was out of ink. Well, turns out we were out of ink, too, so Rick ran to the store and got more. We had time to kill and the topic turned to cable.She said their cable bill is $170 a month! We cancelled our cable a few weeks ago, and depend on Roku / Netflix / Hulu for our viewing desires. I was trying to explain how the Roku works. All she needed was an internet connection. She really thinks she knows everything and was insisting that I was wrong, that the Roku works via cable. I tried and tried to tell her we no longer have cable and look at all the stuff we can access. She kept insisting she can’t cancel cable because she won’t have any TV at all.
She said, “But my cable is tied in with my internet and a home phone, which we don’t need! If I cancel cable I’ll lose the internet!”
“No, they are 3 separate services.”
“I think you’re wrong, Val. Pretty sure you’re wrong.”
The proof was right there in front of her, but she just refused to understand it.

She also insists that the ink cartridges for her printer are about $120 each, and she can’t get them at Walmart. Well, I asked her to shoot me a picture of her ink cartridges. Haven’t gotten it yet tho.

* Beating my head against the wall. *

Also, she kept asking over and over how much a month I pay for Roku. I said “Nothing. We just bought the box, one time cost of $70 or $80.” Five minutes later she’d ask again.

She sent me a pic of her ink cartridges and I found them online for < $20 apiece. She’ll probably argue that that they aren’t the same ones that she has. She insisted she got them from Dell, but there is a sticker on them that reads “Cartridge World.”