But everyone who wants to make people smile during Christmas rather than frown should consider gift-giving. 

This year in the US, for example, consumers estimate they will spend $942 on Christmas gifts, up from $885 in 2018. In total, gift expenditure should surpass $1 trillion. And there's a good reason behind it.

"Humans are an incredibly social species and one of the things that set us apart is forming and maintaining relationships with others," Daniel Farrelly, a psychologist at the University of Worcester, said. "Gift-giving around holidays, birthdays, graduations or weddings is a great opportunity to reinforce those relationships."

But whatever you buy, don't add a small gift to a big gift — when we receive presents in a bundle, we tend to unconsciously average out their value, so a small thing tacked onto a big one will hurt the latter's impact.

This is called the "Presenter's Paradox," and it was first exposed in a 2012 study of the same name, where participants were offered either an iPod by itself or an iPod with a free download for one song.

When asked how much they would pay for it, those offered the iPod with the cheap download valued it 20% less than those without. However, participants asked to choose which option they would gift, overwhelmingly went with the one that included the download, demonstrating that when it comes to gift-giving we fail to grasp that (sometimes) less is actually more.

But if you run out of ideas, remember that gift cards are not bad. Cash is probably the one thing that has the same value for everybody.

But while gifting cash is popular on some occasions in some cultures, it's not for everyone and can be interpreted as lazy or sometimes even offensive.

"Gift cards have become much more popular over time. And they're also very popular with recipients," said Joel Waldfogel, an economist and the author of a study called "The Deadweight loss of Christmas."

Yes, they aren't perfect — there's still some perceived loss of value and billions of dollars worth of them go unredeemed each year — but they're a better option than a rushed or poorly chosen set of socks.