Years ago, I was working in the service department of our local computer shop and a man came in wanting to buy a monitor. The salesmen were "too busy" to take care of "simple" (read as "low margin") sales like that (although they were first in line to sell a customer a cable). At this time, VGA (running at 640x480) was common place (but only just) and it was, in fact, all we had in stock.
The man was white-haired with a white beard and he was sort of a squirrelly non-talkative type. Without much fuss, I sold him the monitor and went back to fixing computers. He called about an hour later.
"How can I help you, sir?" I asked.
"Well, the doohick won't plug into the thingee. I starts to go, but then it stops short of being all the way plugged in."
Beginning to suspect that the monitor pins might be bent - it was the only thing that sprang to mind that would prevent a monitor cable from going all the way in - I continued, "Okay, now, which is the doohick and which is the thingee?"
He paused for a moment. "The doohick you sold me won't plug into the thingee on the computer."
"Gotcha. Okay, can you look at the end of the plug of the doohick, sir?"
"Sure, I see it, there's little doodads in there."
"Yes, sir, those are called pins. Are they bent?"
"Are the doodads bent? Naw, I can see most of 'em and they look straight."
We went on for a while longer, I got him to look at the thingee on the computer to see if anything was in - or blocking - the holes. No luck. Finally, I asked him to bring both the doohick and the thingee in for me to look at.
The next day, the man showed up with the doohick and the thingee. I pulled out the doohick (the monitor) and looked at it... The doodads (the pins) were, in fact, bent. But I could see how a layman would say they weren't. The 15 individual doodads, themselves, were still straight - as in they were uncurved - but they had been pushed together into a few teepee like structures. Curious, I checked the computer...
*boggle* I didn't even know Epson made computers. He said he had bought it in Argentina for a really good price. It had an 8088 processor, a pair of 5.25" floppies, no hard drive, and CGA graphics. And therein lay the problem. CGA used a 9-pin port and I had sold him a 15-pin VGA monitor. He had been forcing the 15-pin plug into the 9-pin port and had teepeed all of the pins into the 9 available holes. I apologized and tried to sell him a CGA monitor, but, he said they were too expensive (and he was right).
Ed: Exactly who's brilliant idea was it to take an existing plug form-factor and add 6 more pins to it. When old graphics and serial ports were abundant, this kind of thing happened *all the time*. I can't wait until someone designs a new USB port that happens to be a similar size to HDMI or something and the fun starts all over again.