I had carol singers at my door last night- two young lads singing the only carol they know: We Wish You a Merry Christmas.
I told them to come back at Christmas.

I did feel a bit mean but those two are for ever coming to my door -
Can we have our ball back? (Yes, of course)
Trick or Treat (They get chocolate biscuits, but only if they come on the right night)
Can we wash your car? (They want money, but I don't have a car)
Have you got any string? (Why? To play conkers. OK)
Have you got any string? (Why? To make a bow and arrow. OK but don't fire it at each other [chances of those two managing to make anything dangerous are nil])

If I had given them anything last night they would have been back every night till Christmas with the same boring carol.