Having a casual chat with (not so very D)F about home decor and styles of wallpaper when he mentions he used to have black and red walls in the living room of a flat he'd lived in years ago
I asked what he was thinking as it sounded like a dungeon, in jest obviously. In hindsight not all that funny but did make me laugh.. much to his irritation
The grumpy twat took offence and went in a huff, I asked him why he was being so daft and he said because I'm "accusing" him of being the one who chose the colour scheme and therefore making fun of him 
Was I BU to make a joke of the situation or is he being ridiculously childish?