I have told these stories before on mumsnet, but they bear repeating.
We were in a teashop, near Sweetheart Abbey in Scotland, having lunch. Ds1, aged about 13, perused the menu carefully, and then, when the waitress came over, asked her, "What's in the beef sandwich, please?" He wasn't best pleased when she looked like this >
and his loving family all fell around laughing, before saying, almost in unison, "Beef, you numpty!!" What he actually wanted to know was whether there was mustard or horseradish or salad in the sandwich.
To this day, a daft question asked by a member of the EvilWolef family, is known as a 'Beef Sandwich' question.
He managed another, aged about 15, when we arrived at a holiday cottage and he was helping to unpack the car. He came in carrying my pillow (I am a sensitive flower, and need to take my own pillow with me on holiday), and asked, "Where shall I put this, mum?" "In the bedroom, perhaps, love??!!"