I've got several funny reactions
My mums response was "you're old enough to choose how to live your life.... Ooh doesn't the dog look cute"
I told one friend as he was drinking his beer and about half of the pint came out of his nose, I choose my timing with a bit more care nowdays.
Whilst in hospital last year I was in a private room, dr's & nurses would enter the room, pause, say sorry for entering the wrong room and leave. Then I'd start a slow countdown from 10, as I reached 2 or 1 they'd poke their head around the door to ask if I was Jayne, I almost felt sorry for them