It turns out the child left a note that read: "Thank you for spreading Christmas joy! We love your lights!" "I read the card and I thought, 'Oh my goodness, this is so delightful!'" said Sullivan.

It is a lesson that Geoffrey Willans's 1950s comic creation, Nigel Molesworth, clearly hadn't assimilated when he penned his refreshingly honest Self-Adjusting Thank You Letter: "Dear aunt/uncle ...

You'll be more likely to write a thank you note if you do it soon after receiving a gift or an act of kindness. The general expectation is between one day and two weeks after opening a gift.