Back in the pre-Virgin days when Telewest were laying fibre across London (that'll be the 1990s) they were doing door-to-door visits to sell connections to their network.
At the time I had a girlfriend who was some years older than me, and one day their marketing-droid turned up at her house and went through their spiel of what they could offer with service. Not being so technically minded, she asked if they could come back later when I would be home.
True to their word, he came back, I answered the door and he ran through their spiel and I probed him with a few questions about their network, and their cable TV which seemed reasonable enough. Then to finish off, trying to gauge which pay-TV channels they might be able to sell, he said "And what sort of films does your mother like to watch?"
Momentarily confused, since my mother lives 50 miles away, I paused and then it clicked...
The way the colour drained from his face when I said "That's not my mother you talked to before..." was a sight to behold.