Two good ones in a row just now:
I'm currently the only one in the office and was talking to someone on the phone when a secretary walks in. She borrowed a laptop a week or so ago. Despite my clearly being on the line with someone, she complains that "you guys should check these things before you give them out. THE SCREEN WAS FILTHY. FILTHY!!!" and leaves. I open the laptop and the screen has what looks like 'fresh' sweat all over it.

I set this up for her and I know it didn't look like that when I took it out of the equipment closet.

Regardless, I don't know how the hell she worked on it that way. Why wouldn't you CLEAN IT off?
Then I get the following phone call:
Her: WHAT ARE THESE PROMPTS ON MY SCREEN??? IT SAYS IT NEEDS TO INSTALL UPDATES AND RESTART.
Me: Yes, that's normal. There were updates pushed out last week--
Her: THIS IS A NEW LAPTOP. IT'S NEW.
WHY DOES MY NEW LAPTOP NEED UPDATES?!?!?!?!??!

Me:

Uh...Updates happen all the time. This is normal.
Her: I'VE NEVER HAD THEM BEFORE.
Me: We have always had them pushed out this way.
Her: WELL IT'S INTERRUPTING MY WORK AND SAYING IT WILL RESTART. WHY IS THIS?!?!
I start explaining that this is an automatic process and sometimes you have to restart to finish the installs/updates. Mid-sentence she goes "I SEE THE OPTION TO RESTART I'LL DO THAT NOW" and hangs up.
