I once made this error when my housebound nan sent me to the corner shop for some "milk in a tin" her dementia having erased the brand name from her memory.
I took her back condensed milk and she flipped her lid. "WHAT EXACTLY AM I SUPPOSED TO DO WITH THAT!!!!?"
I mean, I have no idea but what exactly do you do with evaporated milk??? I've not a clue. My milk is from a bottle not a tin!
To make up for it I took the tin home and bought her a few of the correct tins with my weekly shop.
She passed away a few years later and I stood and sobbed the day I found the tin of condensed milk, long-since forgotten in the back of my pantry.
Gawd rest her soul.
(every time I see either tin it brings back the chastising I got 😂)