I had some one call me patronising lately, for telling them that a HDMI to USB cable didn't exist.
I tried to explain to them that they're utterly different technologies with completely different "wires" inside that do different things and that a USB CABLE with a HDMI on the other end isn't possible.
Cue them screaming and shouting down the phone that I am indeed the one who is wrong.
This was for a "friend's mum's" laptop, which I set up in the first place, configuring it to work with the TV via a HMDI cable.
She wouldn't accept that a cable I'd given her was the right thing (A HDMI cable) despite me continually reminding her that I set up the laptop in the first place, so it was a different laptop, or she's simply not looking at the right port.
This went on about about 20 minutes, resulting in her rage quiting the phone call.