I'm a java dev and systems administrator at a small research lab that's part of a Medical University. We just recently published a software tool and one of the first users was an Assistent Professor from another Institute in the same City.

He is semi computer literate. I mean, he's no techy, but he's doing fine. Still, he had some issues with our Software. We usually only provide support via our User Forums and by E-Mail, but in this case my Boss asked me to help him personally.

One day he asked me to come to his office for some simple task. When I arrived he was just in the middle of a phone call with a representative of a Software company. He told me she was doing a live demo of a software similar to ours. I was interested, because it's always good to see what others are doing and so I sticked around.

This is what happened:

Her: "Ok, now you can click here to load the inputfiles." opens a 6GB text file "You can see the progress here."
Him: "That takes quite a long time to load.."
Her: "Yes, that is strange.. May I ask what kind of Computer you have?"
Him: "It has 16GB of RAM and an 8 core processor."

Now, I have to say I saw the specs before, and this was one monster of a desktop machine. 16GB of RAM, Intel Xeon 8 core (with hyperthreading) with I think around 2.4 GHz each).

Her: pulling up the system information "Oh I see you have an 8 core processor."
Him: "Is that not good?"
Her: "Yeah, you know the problem is that with the 8 cores the GHz are actually split between the cores."
sound of my jaw springing open

Her: "You see, you have 2.4GHz split in 8. That means it's actually just 300MHz. Modern PCs nowadays all have more than 2GHz! You should get a new PC."

He looked at me and saw me facepalming really hard. I shook my head to symbolize that he shouldn't believe her.

She then tried to start multiple worker processes for the software. The GUI would then connect to the worker process over the network - or the loopback interface in our case. Perfect for compute clusters. Anyways, after about 10 minutes of her reading instructions on how to set this up (instructions that he also had on the screen and I could read), she came to the part where she had to enter his PC's IP address. Up to this point I was quiet, but now I was about to lose my patience.

Me (to the Professor): "Just enter 127.0.0.1"
Him (to her): "My colleague here told me I can just enter 127.0.0.1"
Her: "No, no we have to find the IP address!"
Me: "127.0.0.1 works too!"
Him: "Are you sure?"
Me: "Trust me."
Her (to him): "Is your computer in a network"
Me (thinking): "You are remoted in on it.. what do you think?!"
Him: "Yes, it is in a network."
Her: "Then it must have a different IP address. 127.0.0.1 is a default IP Address that only computers that are not in a network use."

I gave up there. Just facepalmed again and let her do her thing. Worst of all was that when she found and entered the correct IP address she was all proud "You see? This is the correct address! The other one is not correct if you are in a network!". She later ended the call again emphasizing how important it was for him to buy a stronger PC.

He never bought their software, btw. It was crap anyways. It was pretty cool for the user interface, but it only worked with obsolete algorithms and reference data.