Excel is a Database ...
neopoleon.com
neopoleon.com
There's one dude in sales where I work who consistently (at least once a week) sends us his latest specification as a spreadsheet embedded in a Powerpoint slide. I called him once and tried to explain what he was doing wrong, and I realized I pretty much didn't know how to communicate the level of wrong that is to his mind.
You're not supposed to... well, you know there's a separate program for that, right?
"Yeah, of course. I just stick it in Microsoft Office and send it to you. That's what I've always done."
Yes, but Office has different parts, and you're using the part that's for presentations, and...
"Look, I just click the button to open Microsoft Office, and then I stick the stuff in those columns. Is that really so hard for you guys?"
... at which point I just gave up, because it's not worth the headache to explain this.
You probably expect that airbags and seat belts come as standard items with your car. Would you pay to have self-declared enhanced seat belts installed in your car? From an independent vendor nobody has heard about?