My little story (one of many)
About 8 years ago, went into PC world to buy a PCI 56k new modem. As I walked in, I was confronted by a friendly sales chap who asked if he could help.
"Yes" I replied, "I'm after a modem"
"Modems over here" he said
As I was perusing the different modems, both external and internal, the chap piped up and said "So which kind of modem do you need?". I said I needed an internal PCI one.
"Ok, I think there here somewhere" he said. Then, amazingly he asked me "Actually, what's the difference between an external and internal modem?"
He genuinely had no idea. I felt like being a BOFH, but decided to tell him one is external and the other is internal.
8 years on, they're still no better (except they charge you £££'s for installing things)