My friend once has to wait on people coming to service his gas boiler when the Jehovah's Witnesses came calling.
He said it was very entertaining asking the awkward questions until they left. Passed the time in a more entertaining manner than daytime TV.
I had a flat mate years ago who used to do that. This is an abrieviated version -
'Jehovah's Witnesses? Is that a new religion?
'Oh no, we've been around for years and have lots of members'
'How many members do you think there have been, worldwide, since you were founded, including all the current ones?'
'Oooh, dunno, maybe 100 million.'
'And how many can go to heaven?'
'144,000'
'Not very good odds are they'
'Errrr....'