I guess this one's been around a bit but I'd missed it.
Guy pulls up in a smart 4x4 on a rough housing estate and gets out. Kid says, 'Look after your car for 50p mister?'
Guy says there's no need as he's leaving his rottweiler in the back.
'Wow,' says the kid, 'Puts out fires does it?'
Credit to the Guardian, last week some time.