Not sure if this is along the same lines as this thread but it has reminded of a time when dp called his dm.
It's not unusual for one of his siblings to answer the phone, he has 3 younger sisters so when he asked if his dm was there, and she said no he asked where she was etc...
Eventually she said it was a wrong number and it was an important call so he got a bit wound up and had a go in that sibling way that turns you back into a child. For about 5 minutes he was moaning to stop dicking around and put his mum on the phone, he didn't have time for this etc. She hung up. He checked the call history...it was a wrong number. I laughed for ages but some poor woman had been verbally abused because he dialled wrong!
There's a lovely lady who owns a little gift shop type thing that I visit regularly and she makes huge effort to interact with her customers but she always gets it wrong. And I don't correct her because that would be worse.
I've been in shopping with my dm, looking at something and my dm said no don't buy that, I've got you it for your birthday. The lady nods along going "yes she has, she came in last week saying I'm buying this for my daughters birthday" my dm also nodded along and later told me she'd bought the gift on amazon.
Another time, shop lady asked me if I was feeling better after my chesty cough. I hadn't had a cough. She's referred to my ds as a girl multiple times, switching between he/she him/her in the same conversations so I don't even know how to correct her. And once she showed me some products, telling me these were the ones I'd enquired about on the fb page. She told me all about them and of course I hadn't even joined the fb page. 
She's sooo friendly but just sooo mixed up!