5. Colourful Underwear - Mexico
On the off-chance that you ever meet a Mexican and find them stripping off on New Year's Eve, you'll find that there's a good chance they're sporting either yellow or red underwear, owing to a Mexican superstition that to wear red underwear is to bring the wearer good luck in love throughout the year, and to wear yellow underwear is to bring financial prosperity. So rampant is the tradition that it's reportedly not uncommon to see Mexicans wearing coloured boxer shorts and knickers over their regular clothing, a clever way for the more modest and shy of us to express what they're hoping for in the next 12 months. To be fair, this one's so cute we're surprised it's not adopted by more countries, especially after a few drinks have been imbibed.