I installed car audio and security for a long time and it was rare that we didn't have a stupid customer that didn't know anything about their own car.
A kid came in and had been to the swap meet and bought a $40 amp he wanted installed. I gave him the standard quote of $45 labor and $40 parts, and he said he would just do it himself so just sell him the parts. I rang them up and then he asked what all the wires get connected to? ah, ok the rca and remote wires go between the deck and amp, the speaker wires between the amp and speakers, power wire the battery, ground the the chassis and yer done! he looked at me very confused and asked where he would find the chassis on his car? ---- I had been working on this older guys car that was watching all of this from the waiting room, and I will never forget the look he gave behind the kids back. His head was directly behind the kids before he rolled his eyes and gave the funnies WTF look I had ever seen from a grandfather and I nearly lost it. After the kid left he gave the same look and asked where he could find the chassis?
I had another customer interested in a keyless entry but wasn't sure how they worked. after explaining it 2x I walked her out to my truck to give a live demo in hopes of it making sense to her. AFter I was done, she looked at me and all she could ask was that with this system installed, if I had her keys I could steal her car!? I didn't know how to respond other then to say that yes that is true, but even with out the system installed, if I had her keys I could steal her car. She still didn't get it.........
And I can't tell you how many times I had them on the phone to schedule an install appt and when I would ask what kind of car, they would tell me a blue one... I would ask if they knew the make or model and they would often tell me something like a chevy escort, 90's or so.... If I would tell them that chevy didn't make an escort then it would lead into a 10 min conversation ending with them tellin me I was wrong. I would just write their name and work to be done as no matter what if they said it was a blue 90 chevy escort somehow a silver or tan suburban would show up.
true stories, I was always amazed people could go out an buy a car stereo when they had no idea what kind of car theyhad.