My partner and I got to meet each other for the first time in person a couple weeks ago (We met online).
This occurs in our hotel room while I’m working on a diamond painting (it’s an adhesive canvas with rhinestones. It’s like color by number, but with rhinestones and letters instead of numbers and colors):
Partner: *helping me out by getting the next color of rhinestone ready* How many Ds do you need?
Me: *pauses, looks at them for a moment, then bursts out laughing*
Partner: What? What did I say? Ds?
Me: *laughs harder*
Partner: For heaven’s sake, [my name]! How old are you, twelve?!

This happened a few years ago. Many stores in the UK operate a “Challenge 25” policy, where, if a customer is buying restricted items and looks under 25, the cashier is supposed to ask for ID. I am buying alcohol.
Cashier: “I’m going to have to ask for ID. I’m sorry, it’s our Challenge 25 policy.”
Me: (Handing over my driver’s licence and grinning) “You don’t have to apologise! I’m glad you think I look under 25. I’m 38.”

I am at work, tasking, when a customer approaches me.

Customer: Hi, could you help me figure out these jean sizes?

(A lot of our jeans come in European sizing)

Me: Of course! You just add 22 to your American size. So, if you’re a 6, for example, you’d probably want to go with a 28. (I know this is not always accurate, but we’ve found it generally gets you the correct size)

Customer: My daughter is a 7. What size should she get?

Me: Well, you add 22 to her size, a 7, so that would be 29.

(I always like to explain the math so that it’s easier for them to shop in the future)

Customer: But she’s a 7. What size would that be?

Me: 29

Customer: *holding up a pair of 26* These?

Me: No. Those would be too small. You need a 29. You just need to add 22 to her American size.

Customer: But what size do I need?

Me: 29

Customer: *finally clicks* Oh, okay. Thanks!

Me: No problem! Have a great day!

(I had to sit down after that interaction)

My sons have all had a wonderful swimming teacher at our local swim school. He’s only 17, but my three boys have all had him at a particular level, so we’ve known the teacher for 3 years.
I’m shopping in the supermarket when a teenager happily greets me and my kids. It takes me a second to realise who it is.
Me: Oh [teacher]! I didn’t recognise you with your clothes on!
Him:…
Me…
Him…
Me:…oh god.
I , a middle aged woman with multiple kids and a full trolley, just shouted across a supermarket that I didn’t recognise a teenager with his clothes on.

While putting together a flyer for a social event at a local state university, one of the sponsoring groups sent me their logo. It was in an MS Word document, and it was color clip art with gradient shadows and all, with no transparency. While placing it in with the other professionally-designed sponsor logos, I faded the opacity of the clip art portion in an effort to tastefully save the visual integrity of the poster. I sent the file on.

Minutes later, I returned to my desk and found a voicemail on my phone.

Client: “Hi, this is [Client] from [Organization that sent me the MS Word logo]. Thanks so much for your work on the flyer. Look, we’re trying to get these printed today, and for some reason, the color on our logo clip art is faded. Listen, I have my BFA in graphic design, so I know about this stuff. Your typeface and kerning looks right, but it looks like the clip art didn’t transfer right. The colors aren’t vibrant at all. Can you Pantone-check those or Google the clip art and re-insert it in there? Thanks again for your hard work!”

Shocked, I just updated the file with the clip art as it was sent to me and emailed it.

I’m still trying to figure out how someone with a BFA in graphic design, who knows the terms “kerning” and “Pantone”, could use copyrighted MS Word clip art for her professional logo.